Adam Clarke on Acts 4:22

The man was above forty years old - The disease was of long standing, and consequently the more inveterate; but all difficulties, small or great, yield equally to the sovereign power of God. It is as easy with God to convert a sinner of forty or four-score, as one of ten years old. But he who now refuses to obey the call of God has neither reason nor revelation to support himself even in the most distant hope that he shall get, in a future time, the salvation which he rejects in the present.