John Gill Bible Commentary

Both young men, and maidens,.... These should praise the Lord, the one for their strength, the other for their beauty; and both should remember their Creator in the days of their youth, and fear, serve, and worship him; so they will praise and glorify him, as did Obadiah, Josiah, Timothy, and the four daughters of Philip the evangelist; old men, and children; the former have had a large experience of the providential goodness of God, and, if good men, of the grace of God, and are under great obligation to praise the Lord for all that he has done for them; for they have known him that is from the beginning, and have seen many of his wonderful works, which they should not forget to declare to their children, to the honour and glory of God; and even out of the mouth of "children", of babes and sucklings, who have less knowledge, and less experience, God sometimes does ordain strength and perfect praise to himself; see Psa 8:2; compared with Mat 21:15.