Disobedience to God.
THIS IS GOD’S ORDER FOR NEW TESTAMENT BELIEVERS:
FORBID NOT TO PROPHECY.
SEEK THE BEST GIFTS—TO PROPHECY.
So, no one ever sins--according to TULIP.
The "reprobate" are that way because God deemed them to be so. They are doing God's will.
The saved are saved because God deemed them to be so--they are doing God's will.
I guess the whole story about Jesus writing in the dust and the adulteress never actually happened?