To say a word in fairness here, i believe that salvation can be
given free. By his own words the thief has done nothing to merit
salvation but Jesus granted his request without prejudice.
"
One of the criminals who were hanged railed at him,[d] saying, "Are
you not the Christ? Save yourself and us!" But the other rebuked
him, saying, "Do you not fear God, since you are under the same
sentence of condemnation? And we indeed justly, for we are
receiving the due reward of our deeds; but this man has
done nothing wrong." And he said, "Jesus, remember me when you come
into your kingdom." And he said to him, "Truly, I say to you,
today you will be with me in Paradise."
- Luke 23:39-43 English Standard Version"