The thief on the cross simply believed in Jesus, and said so. He obtained salvation.For several reasons:
1. The Path of Salvation
There is no consistent Christian account of how humans are supposed to be saved, although this is of the utmost practical urgency.
Luke 23:42-43 (NKJV)
42 Then he said to Jesus, "Lord, remember me when You come into Your kingdom." 43 And Jesus said to him, "Assuredly, I say to you, today you will be with Me in Paradise."