Thou wilt prolong the king’s life: and his years as many generations.
The perpetuity of Christ’s kingdom
He prophesieth not simply of the stability of the kingdom in his own person and posterity, but under the type; namely, he speaketh of the perpetuity of the kingdom of Christ, the true King of Israel, for which end he prayeth that mercy and truth may be forthcoming to subjects of Christ, that His kingdom may be prolonged; and so David in his time, and all the saints in their time, may joyfully praise God continually. Whence learn--
1. It is not unusual with God, together with present consolation, and the light of future salvation in Christ, to reveal also and give assurance of great things concerning Christ’s kingdom.
2. The glory of Christ and perpetuity of His kingdom is every subject’s good and comfort, for this is comfort for David, that Christ shall live for ever, that He shall abide before God for ever.
3. The kingdom of Christ, and government of His subjects in His Church, shall be allowed of God, and be protected of God, and blessed of God for ever, however it be opposed by men in the world.
4. The perpetuity of Christ’s kingdom and preservation of His subjects in this life, till they be possessed of heaven, is by the merciful remedying the misery, and removing of the sin which they are subject unto, and by performing of what He hath promised and prepared through Christ to bestow upon them.
5. The best retreat that can be made after wrestling and victory over troubles is prayer and praises; as here David after his exercise prayeth, “O prepare mercy and truth”; and then saith, “unto thee will I sing.”
6. As the main matter of our vows is the moral duty of rejoicing in God, and hearty praising of Him, so renewed experience of God’s mercy and truth towards His people in Christ is the main matter of our joy in Him and praise unto Him: “O prepare mercy and truth,” etc. (D. Dickson.).