Theology

Predestination
http://www.jesus-is-savior.com/False%20Doctrines/infant_baptism_exposed.htm

An issue that has vexed Calvin is predestination. One of the strongest arguments for faith alone is baptism only after one is saved by giving his heart to the Lord Jesus: you must make a choice. Babies can't make choices and thus predestination is inseparably linked with infant baptism. The predestination issue is the whole issue of how can we do wrong if God already knows what we are going to do, for which nobody has an answer, as our knowledge his hemmed in by a Godelian Wall: it is one of those things you must accept by faith and because we are bound by time but not God.

Christ did not become sin
..... Christ became sin for us .... means he took the punishment for sin and God never abandoned him. Christ as a man asked why God abandoned him, as most people would if flogged and nailed to a cross. The whole issue comes down to the limits of human language and trying to use a word that represents to many concepts resulting in Meaningless sentences.

The key term in the KJV is ....." for us ".... it is this for us that saves the specific text from being a Meaningless sentence because sin is defined as: disobedience to God.

Since Christ was obedient unto death he could impossibly have become sin. One can't become sin, no more than one can become the devil himself, only commit sin.

Instead God the Father was with Christ all the way, never abandoning him. Remember that Christ was fully man and fully God. He become hungry and cursed a tree for not having fruit etc.