Charles H. Spurgeon on Psalms 132:12

If thy children will keep my covenant, etc. Lest David's sons, if they be left without law, should live without care, they must know that the succession shall be perpetual; but the promise is conditional; if David's sons conform themselves to God, "if they keep my covenant", whereof they cannot pretend ignorance. And they have an authentic record: the record, "my testimonies"; authentic, "I myself will teach them." You see the king's blessing, it is rely great; but lest the promise thereof be thought too good to be true, God secures the king with a most unchangeable warrant. The warrant is his oath, "The Lord sware"; and this warrant is, 1. Unchangeable, because sincere; he swore in truth. 2. Stable, he will not turn from it. And what could king David desire more for his own house than a promise of such a blessing, and such a warrant of that promise? Yes he might, and no doubt he did desire more; and God also intended to him more than the letter of this promise doth express, even the accomplishment of the truth whereof this was but a type. And what is that? The establishment of the kingdom of Jesus Christ. —Arthur Lake.