John Gill Commentary Acts 4:22

"For the man was more than forty years old, on whom this miracle of healing was wrought." — Acts 4:22 (ASV)

For the man was above forty years old. So that the miracle was the greater, that a man born lame, and who had been so above forty years, should have a cure; and he was the more known to the people, and his testimony met with more credit:

on whom this miracle of healing was showed; both for the good of men, for the glory of God, and for the confirmation of the Gospel of Christ.