John Wesley on 2 Samuel 7:12

And when, &c. - When the time of thy life shall expire. This phrase implies, that his days shall be prolonged to the usual course of nature, and not cut off in the midst, by any violent or untimely death. I will set - I will set up in thy throne, thy posterity, first Solomon, and then others successively, and at last the Messiah. So the following words may be understood, part of his posterity in general, part of Solomon, and part of Christ only, according to the different nature of the several passages.