Teachings regarding Veneration/Respect (as one of the traditional 10 meritorious deeds)

Something similar came up in another topic: this answer references the The Maha Mangala Sutta, one of whose topics is Gārava which (you wrote) is similar to Apacāyana.

Gaaravo: reverence. This includes the proper veneration of the Buddha, Dhamma and Sangha, and respect for parents and teachers, wise people, good persons and elders — in fact, a general high regard for everyone. Even the Buddha after his Enlightenment surveyed the world to try to find a teacher to revere. When he realized that no teacher surpassed his own attainments, then he proclaimed in verse that he would live revering the Dhamma through which Enlightenment had been discovered.

And the arahant-disciples too had reverence for the Buddha as their guide, for the Dhamma, for other senior bhikkhus and for the way of training.

The further one has gone along the path of Dhamma the more reverence one has for it — and for others who also practice correctly. It is not that reverence grows less as one practices! This is a way of estimating one's own position, for if a lot of pride and conceit can be seen then one has not got very far!

How does one show respect or reverence? The Buddha says that one gives such a person a good seat, stands up to receive them, makes way for them and, for religious teachers, one places one's hands together and bows at their feet. This is a blessing resulting in good future births and harmony in the present life.

A search for 'Gāravo' on Access to Insight may find that this word is used in several other suttas also.

You might also look at other related words (for example, possibly Nivāta as a synonym, or Māna as an antonym).

Another practice to consider might be 'prostrations' which is mentioned frequently on this site.

Prostrations are apparently a Theravada practice, though it might be more prevalent in other schools of Buddhism. See for example this answer which tries to explain the "Tradition and purpose of prostration practice".

Upasaka Suminda Sirinath S. Dharmasena encouraged in the discussion under his answer to possibly share some teachings on veneration. Atma tried to expand the originally sketch which starts with namo, and did a surely poor translation into English. It should not be regarded as finished work, a lot of important further aspects are not included yet but still in the sphere of mind. Its also good if you would share possible missing parts and maybe even try to improve it. The topic is a difficult one, since it is such a natural thing for those having grown up in an environment of right view or live in such, while it is hardly ever seen for people used to grow up and live in spheres where such as right view is negated. So the part who knows its benefit would not easy see that there is a lot of lack and start to explain it while the blind part to it would not estimate to miss a important point. Its actually the peak point where Dhamma and no Dhamma collided or better split far apart. Knowing this it is of cause just for those with little dust in the eyes beneficial while for those with lot of gains even a further obstacle in line with there defilement. One of the main doors to break on through the other side (if one considers the lyric rightly):

Respect and Veneration

Table of contents

• Introduction and dedication
• Dedication
• Object of reverence
  • Persons
  • Physical objects
  • Places
  • Places of pilgrimage
  • Graves and Relics
• Actions
  • Actions of reverence
  • Reverence with the body
  • Salutation and flighty Encounter
  • Bow/Prostration
  • Prostrations as a means of practice
  • Deeds while receiving Dhamma
  • Reverence by Speech
  • Salutation title
  • Reverence and Appreciation of Deeds
• Mind state and Benefit of the Practice
• The Power of Reverence
• Reverence and Worshipping in regard of Gods
• Unskilful kind of Reverence
• Duties of giving Respect for Monks and Nuns
• Benefit and Backwards*
  • Benefits form the practice of Veneration*
  • Backwards of the omitting of Veneration*
• Special Practice of Reverence in various Traditions
  • Puja
• See also
• Sources
• Notes and Links

[ * new added]

On who is an elder and thus worthy of veneration:

We have heard, Master Gotama: “The ascetic Gotama does not pay homage to brahmins who are old, aged, burdened with years, advanced in life, come to the last stage; nor does he stand up for them or offer them a seat.” This is indeed true, for Master Gotama does not pay homage to brahmins who are old, aged, burdened with years, advanced in life, come to the last stage; nor does he stand up for them or offer them a seat. This is not proper, Master Gotama.’

“It then occurred to me: These venerable ones do not know what an elder is or what the qualities that make one an elder are. Even though someone is old—eighty, ninety, or a hundred years from birth—if he speaks at an improper time, speaks falsely, speaks what is unbeneficial, speaks contrary to the Dhamma and the discipline, if at an improper time he speaks words that are worthless, unreasonable, rambling, and unbeneficial, then he is reckoned as a foolish childish elder.

“But even though someone is young, a youth with black hair, endowed with the blessing of youth, in the prime of life, if he speaks at a proper time, speaks what is truthful, speaks what is beneficial, speaks on the Dhamma and the discipline, and if at a proper time he speaks words that are worth recording, reasonable, succinct, and beneficial, then he is reckoned as a wise elder.

Uruvela sutta 2 (AN 4.22)

260 A monk is not Elder because his head is gray. He is but ripe in age, and he is called one grown old in vain.

392 Just as a brahmin priest reveres his sacrificial fire, even so should one devoutly revere the person from whom one has learned the Dhamma taught by the Buddha.

Dhammapada: 19 Dhammatthavagga, 26 Brahmanavagga

Ven. Sir. most likely Apacāyana is a word used in the commentaries more particularly appearing Abhidhamma commentaries like Attha,sālinī, Abhidhamm’attha,saṅgaha, Abhidhamm’attha,vibhāvinī, Moha,vicchedanī. (Search for Apacāyana within the Pali Canon returns nothing while other sources are mentioned in the background and introduction in Puñña,kiriya,vatthu Sutta compiled by Piya Tan)

The salient point with regard to practicing Apacāyana is that you dissolve the ego, pride and self-righteousness, within there is the perception of "I". In addition there is sense of gratitude¹ or respect for higher virtue or attainment in the person you are venerating².

As for source I would like to point out the following:

Apacayana means paying respects to those who excel you in age, morality, integrity, wisdom, virtue, etc. Paying respects to elderly persons such as your father, mother, uncle, aunt; offering your seat and making way for those worthy of respect; bowing your head and showing humility, clasping your palms in homage to Bhikkhus, doffing your hat, saluting according to custom, etc. are all signs of respect. However, if you show respect unwillingly to a powerful person out of fear or with some selfish aim, this cannot be called apacayana, because it is pretentious in nature. It only amounts to maya (trickery).

Note: Food for thought - bowing or curtseying is generally accepted as signs of reverence. In Myanmar some people put down whatever load they are carrying and prostate on the roads when they meet Bhikkhus. Some kneel down in the sidewalk or on the platform of a railway station to pay respects to monks and elderly persons. These actions if done with true sincerity, are not to be blamed. But in these days when people have to rush about in busy places, just a bow or a few humble words will suffice the need of apayacana. Kneeling down and prostrating in worshiping on meeting a Bhikkhu on the roads in a Bhikkhu on the roads or in busy crowded places in the presence of alien people are not really necessary.

Source: Abhidhamma In Daily Life / Chapter 6 - Ten Domains Of Meritorious Actions / Domain 4 - Apacayana

Respect as a way of making merit should be known in such acts as getting up from one’s seat, welcoming one’s mother, father, elder brother, elder sister or an elderly person, taking his/her luggage, saluting him, showing him the way, and so on. Or generally, respecting others’ feelings, privileges, property, and life; regarding them with deference, esteem and honour; avoiding degrading, insulting or interrupting them; refraining from offending, corrupting or tempting them. Sadly, today the younger generation lacks respect or reverence.

According to Venerable Nāgasena, in Milindapañha, there are twelve persons who do not pay respect or show reverence to others: a lustful person because of his lust; an angry person because of his anger; a confused person because of his confusion; an arrogant person because of his pride; one devoid of special qualities owing to his lack of distinction; an obstinate owing to his lack of docility; a low minded owing to his low mindedness; an evil man owing to his selfishness; an afflicted owing to his affliction; a greedy owing to his being overcome by greed; and a businessman owing to his working for profit.

It is clear that, in contrast to the above persons, the reverent and respectful man develops his mind (and thereby accumulates merit), for by his attitude he cuts down the defilement of pride and replaces it by wise conduct of humility. Respecting elders and the Saïgha are clear examples of this aspect. Even the respect shown by a novice monk to a bhikkhu falls under this category.

Here again, the good intention that arises in one who shows respect or reverence is the way of making merit in respecting others.

Source: TEN WAYS OF MAKING MERIT by MAHINDA WIJESINGHE

Respectfulness (apacāyana) is the means by which one shows respect (apacayati), acts properly by way of honouring. Traditionally, respect is shown in such ways as when we meet a practising monk, salute him with joined palms, we take his bowl and robe, and offer him a seat and some water as appropriate. A common mark of respect would be to give way to elders when meeting them. “Respect” here should not be taken in the ritual way, which has very little moral value, as the intention behind such an action is not always pure. “Respect” properly means “accepting others as they are,” that is, using our present-moment awareness not to measure or judge others, but to relate to them (especially those near and dear) as if meeting them for the first time. In other words, when we show a sincere interest in people, we are more likely to encourage them to show their better sides. There is also “self-respect,” that is, abstaining from evil or unwholesome deeds through the feeling of moral shame (ottappa), that such negative results would bring disgrace upon us and those close to us.

Source: Puñña,kiriya,vatthu Sutta commentary and analysis by Piya Tan

Since gāravā is a loose equivalent as per the comments the following are the Suttas which has this word: search for gāravā within the Pali Canon.

¹ Especially to those who helped in learning and coming in contact with the Dhamma, especially you teacher, the lineage of Sangha who preserved the teaching, the Buddha as if it was not for the Buddha we will have not come across the Dhamma at all and our Parami is not strong enough to realise it, and the Dhamma itself as even the Buddha kept it as his teacher.

² Garava Sutta