Because God desires that we love as Christ did - not to obey an external law or an obligation, and certainly not to earn salvation. Here is the problem. We are required to perform certain acts - obey the Commandments. However, God does not desire that we account our obedience as our own works, nor does He desire that we do them out of some obligation to earn something. God desires that the inner disposition is pure - that we give of ourselves totally in love to the other. Christ NEVER abandons the moral law. He criticizes the Pharisees because their interneal disposition to WHY they obeyed the Law was not what He wanted.
If someone says the sinner's prayer and then falls away, and I assume you mean on some sort of permanent level, without making any judgment, we are only left with two choices. Either the original prayer was insincere, or God is a liar.
That is a false dilemna. There is a third option that you overlook. When a person falls away from Christianity, it can also mean that that person is freely choosing to return to his former life. Since God loves us, He allows us to have what we want, even if this means eternal separation. God is not a liar. And a prayer made 20 years ago has very little effect on our walk in Christ today, quite frankly.
God promises us that He will carry on the good work He began in us to completion. If the person fell away, it would mean that God bailed. Can't happen.
God's promise presumes that we DESIRE to unite with Him. There is a cooperation between God and man. If a person fell away, it meant that the PERSON bailed, not God.
how can it be that random chance favored God's desires in every case? Did God mold His nature and teachings simply around His foreknowledge of time? Or, does God cause what He wants throughout time?
I don't believe in "random chance". If God's plan and its execution happens simultaneously FOR HIM, then it is not random. Certainly, He is molding things. But He also is able to take our actions into account. What I must say, though, about this subject is that we will likely never discover the interaction between freedom and grace completely. It is one of those things that Catholics call "a mystery". This means we can never plumb the depths of this subject and we just accept what the Church teaches, ensuring that our opinions on the matter remain within the broad bounds of the teaching that Christ left to His Apostles. Quite frankly, I don't think our rational thought will ever successfully figure this out.
Regards
Including all of your previous posts, let's see if I understand you. In the same thought, you say that we do not earn our own salvation, but that we are required, through our own free will, to perform certain acts and cooperate with God by loving others with a pure inner disposition.
Although there is an apparent contradiction on the surface, this is solved by declaring that all the free will choices made, the initial choice and the lifelong fulfillment of the Sacraments, etc., are not "works" in the Biblical sense because they were not done to earn money.
So, all the Biblical passages that say that salvation is by grace through faith, and not by works refer to jobs for pay? Did the Jews or the early Christians believe that we could attain our salvation by doing a job for pay, such that it was necessary for the Bible to clarify this point several times?
When a person falls away from Christianity, it can also mean that that person is freely choosing to return to his former life.
When a person falls away, what happens to the indwelling Spirit? Does He stay there, defeated, or does He depart during the choice of the person to go back to the sinful life?
Since God loves us, He allows us to have what we want, even if this means eternal separation.
Since you are referring to after "initial" salvation (once we become a child of God), I would respectfully disagree. Given the countless comparisons to the parent-child relationship found throughout the Bible, would you allow your child to have what he wanted, even if you knew for sure that it would cause certain death? Is that love?