With regard to the certainty [or assurance] of salvation, my opinion is, that it is possible for him who believes in Jesus Christ to be certain and persuaded, and, if his heart condemn him not, he is now in reality assured, that he is a son of God, and stands in the grace of Jesus Christ. Such a certainty is wrought in the mind, as well by the action of the Holy Spirit inwardly actuating the believer and by the fruits of faith, as from his own conscience, and the testimony of God's Spirit witnessing together with his conscience. I also believe, that it is possible for such a person, with an assured confidence in the grace of God and his mercy in Christ, to depart out of this life, and to appear before the throne of grace, without any anxious fear or terrific dread: and yet this person should constantly pray, "O lord, enter not into judgment with thy servant!"
But, since "God is greater than our hearts, and knoweth all things," and since a man judges not his own self--yea, though a man know nothing by himself, yet is he not thereby justified, but he who judgeth him is the Lord, (1 John iii. 19; 1 Cor. iv. 3,) I dare not [on this account] place this assurance [or certainty] on an equality with that by which we know there is a God, and that Christ is the saviour of the world. Yet it will be proper to make the extent of the boundaries of this assurance, a subject of inquiry in our convention.