Acts 9:4 records the original words of Jesus to Saul on the road, providing the source for Paul's citation here.

Acts 22:8 gives another account of Jesus' identification, corroborating Paul's testimony in his defense.

Matthew 25:40 directly parallels Jesus' identification: serving the least is serving Christ, just as persecuting them is persecuting him.

Matthew 25:45 states the inverse: failing to serve the least is failing to serve Christ — same principle of identification.