WLC Q.81: Are all true believers at all times assured of their present being in the estate of grace, and that they shall be saved?
Assurance of grace and salvation not being of the essence of faith, (Eph. 1:13) true believers may wait long before they obtain; (Isa. 50:10, Ps. 88:1–3,6–7,9,10,13–15) and, after the enjoyment thereof, may have it weakened and intermitted, through manifold distempers, sins, temptations, and desertions; (Ps. 77:1–12, Cant. 5:2–3, 6, Ps. 51:8,12, Ps. 31:22, Ps. 22:1) yet they are never left without such a presence and support of the Spirit of God as keeps them from sinking into utter despair. (1 John 3:9, Ps. 73:15,23, Isa. 54:7–10)
This infallible assurance doth not so belong to the essence of faith, but that a true believer may wait long, and conflict with many difficulties, before he be partaker of it: (1 John 5:13, Isa. 50:10, Mark 9:24, Ps. 88, Ps. 77:1–12) yet, being enabled by the Spirit to know the things which are freely given him of God, he may, without extraordinary revelation in the right use of ordinary means, attain thereunto. (1 Cor. 2:12, 1 John 4:13, Heb. 6:11–12, Eph. 3:17) And therefore it is the duty of every one to give all diligence to make his calling and election sure, (2 Pet. 1:10) that thereby his heart may be enlarged in peace and joy in the Holy Ghost, in love and thankfulness to God, and in strength and cheerfulness in the duties of obedience, (Rom. 5:1–2, 5, Rom. 14:17, Rom. 15:13, Eph. 1:3–4, Ps. 4:6–7, Ps. 119:32) the proper fruits of this assurance; so far is it from inclining men to looseness. (1 John 2:1–2, Rom. 6:1–2, Tit. 2:11–12, 14, 2 Cor. 7:1, Rom. 8:1, 12, 1 John 3:2–3, Ps. 130:4, 1 John 1:6–7)