We absolutely can have assurance of salvation. This surety is predicated on God’s inerrant and infallible Word.
We are saved by Christ’s secure grip on us, not our grip on Him.
We are preserved by God’s grace. The following Scriptures give clear and direct evidence of assurance of salvation.
Sadly, the sacramental churches, such as Catholicism and Orthodoxy, do not affirm the principle of Sola Scriptura. Their theologians and apologists tie themselves into mental knots trying to explain away the clear teaching of Scripture, namely assurance of salvation.
The Westminster Confession of Faith beautifully defines what biblical assurance is.
Although hypocrites, and other unregenerate men, may vainly deceive themselves with false hopes and carnal presumptions of being in the favour of God, and estate of salvation (which hope of theirs shall perish): yet such as truly believe in the Lord Jesus and love Him in sincerity, endeavouring to walk in all good conscience before Him, may, in this life, be certainly assured that they are in the state of grace, and may rejoice in the hope of the glory of God, which hope shall never make them ashamed.
WCF 18.1: Hope of Assurance
This certainty is not a bare conjectural and probable persuasion grounded upon a fallible hope; but an infallible assurance of faith founded upon the divine truth of the promises of salvation, the inward evidence of those graces unto which these promises are made, the testimony of the Spirit of adoption witnessing with our spirits that we are the children of God, which Spirit is the earnest of our inheritance, whereby we are sealed to the day of redemption.
WCF 18.2: Grounds of Assurance
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: 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. And therefore it is the duty of every one to give all diligence to make his calling and election sure, 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, the proper fruits of this assurance; so far is it from inclining men to looseness.
WCF 18.3: Means and Fruits of Assurance
True believers may have the assurance of their salvation divers ways shaken, diminished, and intermitted; as, by negligence in preserving of it, by falling into some special sin which woundeth the conscience and grieveth the Spirit; by some sudden or vehement temptation, by God’s withdrawing the light of His countenance, and suffering even such as fear Him to walk in darkness and have no light: yet are they never utterly destitute of that seed of God, and life of faith, that love of Christ and the brethren, that sincerity of heart, and conscience of duty, out of which, by the operation of the Spirit, this assurance may, in due time, be revived; and by the which, in the mean time, they are supported from utter despair.
WCF 18.4: Loss and Recovery of Assurance
Here are some relevant scriptures.
Being confident of this, that he who began a good work in you will carry it on to completion until the day of Christ Jesus.
Philippians 1:6
For God’s gifts and his call are irrevocable.
Romans 11:29
And you also were included in Christ when you heard the message of truth, the gospel of your salvation. When you believed, you were marked in him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession—to the praise of his glory.
Ephesians 1:13-14
For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.
Romans 8:38-39
That is why I am suffering as I am. Yet this is no cause for shame, because I know whom I have believed, and am convinced that he is able to guard what I have entrusted to him until that day.
2 Timothy 1:12
I give them eternal life, and they shall never perish; no one will snatch them out of my hand.
John 10:28
I write these things to you who believe in the name of the Son of God, that you may know that you have eternal life.
1 John 5:13
Because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.
Romans 10:9
Blessed be the God and Father of our Lord Jesus Christ, who according to His abundant mercy has begotten us again to a living hope through the resurrection of Jesus Christ from the dead, to an inheritance incorruptible and undefiled and that does not fade away, reserved in heaven for you, who are kept by the power of God through faith for salvation ready to be revealed in the last time.
In this you greatly rejoice, though now for a little while, if need be, you have been grieved by various trials, that the genuineness of your faith, being much more precious than gold that perishes, though it is tested by fire, may be found to praise, honor, and glory at the revelation of Jesus Christ, whom having not seen you love. Though now you do not see Him, yet believing, you rejoice with joy inexpressible and full of glory, receiving the end of your faith—the salvation of your souls.
1 Peter 1:3-9
