Psalms 138:8

The Lord will perfect that which concerneth me - He will complete what he has begun. He will not begin to interpose in my behalf, and then abandon me. He will not promise to save me, and then fail to fulfill his promise. He will not encourage me, and then cast me off. So of us. He will complete what he begins. He will not convert a soul, and then leave it to perish. “Grace will complete what grace begins.” See the notes at Philippians 1:6.

Thy mercy, O Lord, endureth for ever - See the notes at Psalms 136:1.

Forsake not the works of thine own hands - What thou hast made; what thou hast begun to do. Do not leave me to perish. Prayer is one of the means - and an essential means - by which the saints are to be kept unto salvation. The doctrine of the “perseverance of the saints.” is not inconsistent with prayer, but rather prompts to it; and he who professes to rely on that doctrine, and feels so safe that he does not need to pray, and does not pray, gives certain evidence that he has never been converted, and has no true religion.