Well, if you will recall, the thief on the cross died before the church was instituted on the Day of Pentecost. He died under the old law. The mission of Christ had not yet been fulfilled when the thief on the cross died. The mission/work of Christ did not finish until 3 days after the thief died. That being when Christ was raised from the dead. You cannot compare the two. They are under different dispensations. One the law of Moses, and the other under the law of Liberty/the Law of Christ.
Okay. Then if I commit the sins of the 10 commandments I am not sinning? Only those in Gal 5:19 count because it was after the day of Penecost?
That argument falls flat because some of the Scripture you use out of context is also happening before the death of Christ. But none the less, you should remember what salvation was of in that "different dispensation."
Romans 4:1 ¶What shall we say then that Abraham our father, as pertaining to the flesh, hath found?
2 For if Abraham were justified by works, he hath whereof to glory; but not before God.
3 For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness.
4 Now to him that worketh is the reward not reckoned of grace, but of debt.
5 But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
6 Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works,
7 Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered.
8 Blessed is the man to whom the Lord will not impute sin.