The attaining of assurance faces many difficulties. When a person feels the guilt of his sins, he is quick to look upon God as an enemy and an avenger. Our hearts are deceitful. We are prone to neglect our walk with God and be spiritually careless, but assurance is preserved by a continual exercise of grace (2 Peter 1:10). Satan attacks us with his fiery darts, and if he cannot hurt us in our obedience, he will attack us in our comforts. Pirates wait for the ships most full of gold, and Satan leaves the wicked in peace while tempting the godly with many fears. Even God sometimes hides Himself so that we will not take assurance for granted and grow lazy.
It is possible for a Christian to have an assurance of his salvation. We see in Scripture that God’s people have enjoyed it. David called God his God and his portion, and thanked Him for forgiving his sins. Paul showed his assurance, and based it not on a special revelation from God but on grounds that belong to all the people of God (Rom. 8). If a man can confess that he believes in God and in other divine truths of the Word, surely he can also know he believes. God gave the sacraments of baptism and the Lord’s Supper as signs and seals of his covenant. To throw away the possibility of assurance is to throw away God’s seals. If assurance is not possible, then there must be some problem with its object or the means by which we get it. But the object of assurance is the promises of God, which are yes and amen in Christ (2 Cor. 1:20), and the means of assurance is the Spirit of God, who renews the heart to sincerity and effectively works assurance.
We need assurance. The nature of faith is to establish and settle us. It is a pillar and anchor to the soul. Though one can have faith without assurance, doubting and fear are the opposite of believing. Trusting in God is compared in the Bible to rolling ourselves on Him, staying the mind on Him, and resting the heart on Him. Strong and regular exercises of faith in Christ will, over time, bring us to assurance. It is also needed so that we can praise God for His mercies, have more joy and peace in our hearts, and be stirred up to serve Him with greater holiness. Hope leads a Christian to purify himself (1 John 3:3), promises move him to cleanse himself (2 Cor. 7:1), belief motivates him to speak (2 Cor. 4:13), and knowledge of the Father’s love makes the child willing and ready to obey (Eph. 5:1; Col. 3:12).