Why do Christians appeal to personal gain and inducing fear when attempting to "convert" people?

I liked the last answer offered by Pterandon, but I'd like to expand on it if I might. Ultimately, the questions seems to be what's the most effective way to appeal to the lost. In this age of moral relativism, bringing up sin or hell as a "stick" has little impact since most people (adults, at least) are more likely to believe in space aliens than the truth of the bible - the authority underpinning "sin" and "hell".

So what are we left with as a carrot?

Prosperity might be an effective pursuader, but it's entirely unbiblical (IMO) and ultimately will only produce poor-quality believers.

What I'm trying is the idea of completeness. It's the idea that we're going to remain lonely, empty and ultimately unfulfilled without God in our lives; that even if we have everything we could ever dream of, the weight of our incompleteness without God will continue to bear down on us. Thus you see beautiful, young, rich people like Angelina Jolie desperately trying to redeem their souls and find completeness in doing good.

So while the bible may have lost credibility as the source of TRUTH, when I stand there in front of someone who's seeking answers, I can tell them honestly that I've found fulfillment in the life I get from my relationship with God. The bible they can dismiss, but when I look them in the eye and tell them what I've seen, felt and heard, they can't dismiss that.

Religion is the construct people make up to feel closer to God, but Jesus' offer is always the same: "Follow Me" or "Come unto Me". And in doing that, not just once but every day, I find fulfillment, joy and peace that's not contingent on the circumstances of my life.

Tolstoy famously wrote in Anna Karenina, “All happy families are alike; each unhappy family is unhappy in its own way.”

A doctor must treat each disease with a different treatment. When the Great Physician confronts the many sicknesses (physical and spiritual) that afflict humanity, he likewise applies different remedies, and varies his appeal. There may be one Jesus and one Cross, but consider how one man needed sight, a woman the closing of a wound, a girl a resurrection and a leper a cleansing.

I consider it fascinating how in Islam, they require all to learn Arabic to understand the Koran properly, whereas Christian groups like Wycliffe Bible Translators are furiously attempting to translate the Bible into every language in the world so as to make a specific appeal to each culture.

It is in a similar vein that Christians appeal to the fire of Hell and the Glories of Heaven when teaching others about our faith. Some will be reached, some will be moved, some will change their ways when hearing such arguments, just as some were moved by miracles to believe in Jesus.

Did not Rahab fear the Israelites and their God and so protect the spies? Her reward was to be joined to Israel and appear in the lineage of Christ.

I once performed a study of all the parables of Jesus. I concluded that slightly over half dealt with Heaven, slightly over half dealt with Hell, with much overlap. So Jesus made such an appeal to his hearers, but those arguments were not the only approaches he employed.

If you survey great Christian literature, what do you find. Inferno (about Hell), Pilgrim's Progress (which begins in the City of Destruction), The Great Divorce (Heaven and Hell).

Hebrews 11 says: "And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him." The emphasis is on faith in God and loving God, but the earnestly seeking reward (in this context, the promised land, Heaven) is the demonstration of the faith. I seek Heaven, not because it is like Disney World, but because knowing the character of God and the love he has for me, I know that being with him there is the best thing in the world. Likewise Hell, the place where his love and presence is absent, is Hell not only because of the torment, but because the God I love will not be there.

Additionally, I did a study of those things that that the Bible teaches us to value, the so-called treasures in heaven that Jesus urges us to pursue instead of Earthly gain and money (as found in the sermon on the mount in Matthew 5-7). Having come up with a list of ten spiritual treasures (another student of the Bible may come up with a longer or different list), I was surprised to find that the passages in Proverbs, Ecclesiastes and Psalms that cite the fear of the Lord connect that fear to EVERY ITEM ON MY LIST!!! Thus the fear of the Lord is a cause or basis of the acquisition of all truly good things.

So if many who attempt to argue the merits of Christianity and motivate others to follow its teachings appeal to fear and offers of gain, they may go about it wrong (such as the Health and Wealth movement preachers did and do), but that does not invalidate such approaches entirely. The person who led me to faith spoke in unflinching terms about my rebellion against God and the consequences of such a life if I did not repent. That person was blunt and unapologetic. I heard them and I changed. Such an appeal might repel another person, but thankfully, God knows which message to use on each person and chooses his messengers carefully.

Fear of The Lord is the beginning of wisdom. Whenever one goes to confession they're asked to recite the act of contrition a normal form of which includes something along the lines of:

because I dread thy just punishements.

But ends with saying I'm sorry because:

but most of all because I have offended you who are All Good and deserving o all my love.

And that's the end of wisdom or at least the better part of wisdom.

Also, it's not a 'good kind of fear' the word my fairly liberal minded, but probably correct pastor uses is revere. It's giving God the respect He deserves. Not being overly familiar with Him to the point you feel as though you can box Him in. And accepting that God alone has the ability to judge us justly at the end of our earthly life.

Some people don't want to give this ability to God because they dogmatically cling to an argument that a loving God would abandon justice for mercy. And, whereas it was revealed (privately) to St. Faustina that Mercy is God's greatest attribute it would not be a loving act (and therefore not an act of God) to take away our free will which gives us the ability not to choose to seek Him and not to desire to live with Him forever.

Promises of wealth and threats of hell are not only ineffective means of evangelism, they don't even address what is at stake in conversion.

Allow me to quote from two Christian sources before making my case. First, the parable of the Pharisee and the Publican is relevant here.

To some who were confident of their own righteousness and looked down on everyone else, Jesus told this parable: “Two men went up to the temple to pray, one a Pharisee and the other a tax collector. The Pharisee stood by himself and prayed: ‘God, I thank you that I am not like other people—robbers, evildoers, adulterers—or even like this tax collector. I fast twice a week and give a tenth of all I get.’ “But the tax collector stood at a distance. He would not even look up to heaven, but beat his breast and said, ‘God, have mercy on me, a sinner.’ “I tell you that this man, rather than the other, went home justified before God. For all those who exalt themselves will be humbled, and those who humble themselves will be exalted.” (Luke 18:9-14)

Secondly, here is a quote from The Defense of the Augsburg Confession, one of the early documents of Lutheranism:

Likewise the faith of which we speak exists in repentance, i.e., it is conceived in the terrors of conscience, which feels the wrath of God against our sins, and seeks the remission of sins, and to be freed from sin. And in such terrors and other afflictions this faith ought to grow and be strengthened.

If you try to evangelize someone who "feels the wrath of God against their sins," someone who understands their need for mercy of their sins, the work is very easy. Those other promises, especially wealth, aren't even a motivator.

If you try to evangelize someone like the Pharisee, who has no conviction of sin, can only see the greater sins of others, then you have a bigger problem. If you get them to make some kind of spiritual gesture because of the promise of wealth, or because of the promise of avoiding an arbitrary and undeserved hell, it is fair to ask whether there were a true conversion.

I can't do any better than C. S. Lewis's sermon The Weight of Glory (my apologies for basically simply quoting this and moving on, but this is at the crux of the matter). This is expounding on what Thomas Shields has already said, but I do love the way Lewis says it.

If you asked twenty good men to-day what they thought the highest of the virtues, nineteen of them would reply, Unselfishness. But if you asked almost any of the great Christians of old he would have replied, Love. You see what has happened? A negative term has been substituted for a positive, and this is of more than philological importance. The negative ideal of Unselfishness carries with it the suggestion not primarily of securing good things for others, but of going without them ourselves, as if our abstinence and not their happiness was the important point. I do not think this is the Christian virtue of Love. The New Testament has lots to say about self-denial, but not about self-denial as an end in itself. We are told to deny ourselves and to take up our crosses in order that we may follow Christ; and nearly every description of what we shall ultimately find if we do so contains an appeal to desire. If there lurks in most modern minds the notion that to desire our own good and earnestly to hope for the enjoyment of it is a bad thing, I submit that this notion has crept in from Kant and the Stoics and is no part of the Christian faith. Indeed, if we consider the unblushing promises of reward and the staggering nature of the rewards promised in the Gospels, it would seem that Our Lord finds our desires, not too strong, but too weak. We are half-hearted creatures, fooling about with drink and sex and ambition when infinite joy is offered us, like an ignorant child who wants to go on making mud pies in a slum because he cannot imagine what is meant by the offer of a holiday at the sea. We are far too easily pleased.