Seeking sources on -- practicing for this life alone is not even Dharma

I'm going to add an answer of my own based on some reading I did today (but still give the nod to Sadhana for a good citation).

This piece -- The Truth of Rebirth, by Thanissaro Bikkhu -- makes the point that "birth" in the first of the Four Truths can only refer to rebirth, otherwise why would it be relevant to an already born being. It also cannot refer simply to micro-level, momentary mind-states because the Buddha is quite clear (SN 12:2) that he means the literal birth of a person, and likewise illness, aging and death. And for all, he means cyclic repetition of them.

This and numerous other points, particularly Paticca Samuppada (dependent arising) make it clear the the Four Truths are intimately bound up with literal rebirth. So any view that denies rebirth also denies the Four truths, that is, Dharma.

The only remaining question for me is the person who acknowledges the truth of rebirth but is still not motivated by it. But to do that is clearly not to practice Dharma either, since intention and action are a crucial elements of practice.

So bottom line, I think the Lam Rim formulation is a forceful summary of these facts, which is deeply built into the fundamental Pali Canon teachings but scattered around. (Plug for Lam Rim -- it claims to be a succinct, systematic gathering of the fundamental teachings, both Pali Canon and Mahayana. I think this example demonstrates that quality rather nicely.)

I don't see how this isn't obvious.

1. bodhichitta
2. renunciation
3. better rebirth
4. long life, good health

The first three are all (aspects of, mentioned in, included within) Dharma.

"Better rebirth" at least allows you to detach from a view of self-is-this-body.

"Long life, good health" are slightly mentioned as possibilities (for example inasmuch as it's recommended not to eat too much, which is beneficial in this life), but practicing only for that motive seems to me to originate in (and to sustain) a view that's contrary to Dharma, which says for example:

• Be heedful of the current moment
• No guarantee about the future, except that all compound things will decay
• Attachment (e.g. to long life, good health) causes suffering

So that view or intention seems to me to be contrary to the noble truths, contrary to the eightfold way ... if it's not Dharma ... if, therefore, it's not Buddhism ... then I don't see how it isn't obvious that it's likely that the "hoped for effect won't happen":

• If the "hoped-for-effect" is the benefit-of-practising-Buddhism (e.g. happiness of renunciation) then the effect won't happen if you're not practising Buddhism
• If the "hoped-for-effect" is benefit-to-health then, if you're only pretending to practice Buddhism (e.g. "reciting the same amount of words"), practising it badly or falsely, why should that have any effect at all?

Parting from the Four Attachments :a short teaching spoken by Manjushri to the Sakya patriarch Sachen Kunga Nyingpo:

If you are attached to this life, you are not a true spiritual practitioner.
If you are attached to samsara, you do not have renunciation.
If you are attached to your own self-interest, you have no bodhichitta.
If there is grasping, you do not have the View.

This first line addresses this exact point: if your only concern is for this present life, then you can't practice. Actually, your first practice can be changing this attitude!

As per Theravada tradition Dhamma has the quality of Paccattaṃ veditabbo viññūhi (To be meant to perceive directly and this experience in withing this life time), Sandiṭṭhiko (can be examined and the results been seen here and now), Akāliko (timeless and immediate results when practiced correctly). All this leading to the fact that you should practice for this life time though the benefits would also manifest in substantial life times if you do not get fully liberated in this life.

You need some level of motivation otherwise you will not,

• put the effort, or
• be diligent in the way on how to practice.