My mercy shall not depart ... - Hence, Isaiah’s saying, the sure mercies of David Isaiah 55:3, i. e. unfailing, lasting mercies: mercies which are like streams of water that never dry up Isaiah 33:16; Jeremiah 15:18. This is explained in 2 Samuel 7:16, where the word established is the same word as is rendered sure in Isaiah.
Before thee - Before Me is probably the true reading in 2 Samuel 7:15-16 (if the rest of the text be sound), according to the analogy of Jeremiah 35:19; 1 Samuel 2:30, 1 Samuel 2:35; and many other places; whereas the idea contained in the reading, before thee, is unparalleled. But the reading in 1 Chronicles 17:13 is quite different: “As I took it from him that was before thee,” meaning Saul, which gives a very good sense, and suggests that the text here may have been corrupted.