A man may as truly say, the sea burns, or fire cools, as that certainty of salvation breeds security and looseness.Commentary on the Old and New Treatments, 5
If you have a good hope be zealous and watchful over it. Beware that Satan does not steal it away for a season, as he did from David and Peter. Beware that you do not lose sight of it by giving way to inconsistencies, and by conformity to the world. Examine it often, and make sure that it is not becoming dimOld Paths, Chapter 4
the proof or validation of genuine conversion is that the one who professes faith in Christ perseveres in that faith and grows in sanctification throughout the full course of his life. If a person professes faith in Christ and yet falls away or makes no progress in godliness, it does not mean that he has lost his salvation. It reveals that he was never truly converted.
remember that our salvation goes back even before the beginning of our faith, into eternity past. Salvation begins in election. This is an even more ultimate reason why we will persevere. In chapter 11, I quoted Romans 8 at some length. Note there how the apostle Paul connects election and perseverance. Paul sees a golden chain: from God's foreknowledge and predestination in eternity past, to calling and justification, to glorification. Those who are predestined to be conformed to the image of Christ cannot fail to be glorified. So we hear the language of perseverance.Systematic Theology: An Introduction to Christian Belief (Kindle Locations 25705-25709). P&R Publishing. Kindle Edition.
other passages put the point even more strongly: we have eternal life here and now, not only in the future: "Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him" (John 3:36 ); "Truly, truly, I say to you, whoever hears my word and believes him who sent me has eternal life. He does not come into judgment, but has passed from death to life" (John 5:24);Systematic Theology: An Introduction to Christian Belief (Kindle Locations 25705-25709). P&R Publishing. Kindle Edition.
Notice also John 10:27-29: "My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father's hand." Nobody can snatch a believer out of God's hand. These verses speak of eternal life in the future for those who believe today.Systematic Theology: An Introduction to Christian Belief (Kindle Locations 25705-25709). P&R Publishing. Kindle Edition.
It is maintained that the life of regeneration and the habits that develop out of it in the way of sanctification can never entirely dissapearSystematic Theology, Chapter XI
God does, indeed, by his grace and through his Spirit, work to preserve his people so that they will be vindicated in the judgment; but, at the same time, God's people are responsible to persevere in their faith if they expect to see that vindicationThe letters to the Colossians and to Philemon (p. 144). Grand Rapids, MI: William B. Eerdmans Pub. Co.
Perseverance may be defined as that continuous operation of the Holy Spirit in the believer, by which the work of divine grace that is begun in the heart is continued and brought to completion. It is because God never forsakes His work that believers continue to stand to the very end.Systematic Theology, 546.
Perseverance is not the means by which we get God to be for us; it is the effect of the fact that God is already for us. You cannot ever make God be for you by your good works because true Christian good works are the fruit of God's already being for you. (If you get it turned around, you will commit spiritual and eternal suicide.) Stand: A call for the Endurance of the Saints (Page 42) (Bracketed part is from a sermon with the same point)
Only let a sinner lay hold on Christ by faith and then however feeble, Christ's word is pledged to him, "I will never leave thee nor forsake thee." He may correct him occasionally in love. He may gently reprove him at times. But He will never, never give him up. Holiness (Chapter 12)