Here the whole Church is supposed as engaged in this hymn of praise. In the former part, it was the song of one: I will praise thee. In this, it is, Praise ye the Lord. And they are not only praising Jehovah in songs of redemption themselves, but stirring up all others to the same devout and becoming exercises. Everything forms motives to praise Jehovah's glory in himself; Jehovah's glory in giving grace to his people; all, and every view of him, in the excellent things he hath done, demands the tribute of thanksgiving: and this is known in all the earth! Reader! think how wretched must that soul be, and how much the harp of melody in his own heart must be out of tune, that can find no cause in himself and his own experience to join the chorus!
Related Commentaries of Isaiah 12:4
Isaiah 12:4-5
4 And in that day shall ye say, Praise the LORD, calla upon his name, declare his doings among the people, make mention that his name is exalted.
5 Sing unto the LORD; for he hath done excellent things: this is known in all the earth.