Assurance will help a man to bear poverty and loss. It will teach him to say, “I know that I have in heaven a better and more enduring substance. Silver and gold have I none, but grace and glory are mine, and these can never make themselves wings and flee away. Though the fig tree shall not blossom, yet I will rejoice in the Lord” (Hab. 3:17, 18).
Assurance will support a child of God under the heaviest bereavements and assist him to feel “It is well.” An assured soul will say, “Though beloved ones are taken from me, yet Jesus is the same, and is alive for evermore. Christ, being raised from the dead, dieth no more. Though my house be not as flesh and blood could wish, yet I have an everlasting covenant, ordered in all things and sure” (2 Kings 4:26; Heb. 13:8; Rom. 6:9; 2 Sam. 23:5).
Assurance will enable a man to praise God and be thankful, even in prison, like Paul and Silas at Philippi. It can give a believer songs even in the darkest night and joy when all things seem going against him (Job 35:10; Ps. 42:8).
Assurance will enable a man to sleep with the full prospect of death on the morrow, like Peter in Herod’s dungeon. It will teach him to say, “I will both lay me down in peace and sleep, for Thou, Lord, only makest me dwell in safety” (Ps. 4:8).
Assurance can make a man rejoice to suffer shame for Christ’s sake, as the apostles did when put in prison at Jerusalem (Acts 5:41). It will remind him that he may “rejoice and be exceeding glad” (Matt. 5:12), and there is in heaven an exceeding weight of glory that shall make amends for all (2 Cor. 4:17).
Assurance will enable a believer to meet a violent and painful death without fear, as Stephen did in the beginning of Christ’s church, and as Cranmer, Ridley, Hooper, Latimer, Rogers and Taylor did in our own land. It will bring to his heart the texts: “Be not afraid of them which kill the body, and after that have no more that they can do” (Luke 12:4). “Lord Jesus, receive my spirit” (Acts 7:59).
Assurance will support a man in pain and sickness, make all his bed, and smooth down his dying pillow. It will enable him to say, “If my earthly house fail, I have a building of God” (2 Cor. 5:1). “I desire to depart and be with Christ” (Phil. 1:23). “My flesh and my heart may fail, but God is the strength of my heart, and my portion for ever” (Ps. 73:26). (Taken from Holiness, It's Nature, Hindrances, Difficulties and Roots, by J.C. Ryle)