Saturdays with Calvin #67

[L]et us remember, that the completion of the Divine mercy depends not on the works of believers, but that God himself fulfill the promise of salvation to those who by right conduct correspond to their calling, because he recognizes the true badges of sons in those only who are directed to good by his Spirit. To this we may refer what is said of the members of the Church, “Lord, who shall abide in thy tabernacle? who shall dwell in thy holy hill? He that walketh uprightly, and worketh righteousness, and speaketh the truth in his heart,” &c. (Ps. 15:1, 2). Again, in Isaiah, “Who among us shall dwell with the devouring fire? who among us shall dwell with everlasting burnings? He that walketh righteously,” &c. (Isa. 33:14, 15). For the thing described is not the strength with which believers can stand before the Lord, but the manner in which our most merciful Father introduces them into his fellowship, and defends and confirms them therein. For as he detests sin and loves righteousness, so those whom he unites to himself he purifies by his Spirit, that he may render them conformable to himself and to his kingdom. Therefore, if it be asked, What is the first cause which gives the saints free access to the kingdom of God, and a firm and permanent footing in it? The answer is easy. The Lord in his mercy once adopted and ever defends them.

Institutes of the Christian Religion 3.17.6 John Calvin, translated by Henry Beveridge, Hendrickson, pg, 531.