God has sworn two blessings of salvation for the elect. First He promised to keep them forever, and never forsake them. Second, He promised to work within them so that they will not fall away from Him. Both blessings are expressly promised in Jer. 32:40.

The Fifth Point of Calvinism take it title from Rev. 13:10 and 14:12, the Perseverance of the Saints. God promised to preserve the elect, and once they are saved they most certainly are preserved, kept and guarded by God Himself (Psa. 37:28, 66:9, 97:10, 145:14,20; 1 Tim. 1:12). God swore never to leave or forsake the elect (Psa. 94:14; Heb. 13:5). Jesus promised that He would never cast out any who came to Him (John 6:37). The elect are kept in the same way in which they were saved in the first place, namely, by the invincible power of God (1 Pet. 1:5).

This is especially explicit in John 10:28, where Jesus says "I give them eternal life, and they shall never perish; and no one shall snatch them out of My Hand." The elect are eternally secure in the hands of Christ and the Father. God keeps them safe from Satan (1 John 5:18; John 17:11, 12, 15; 2 Thess. 3:3;Luke 22: 31-32). It is true that the elect slip and fall into sin. But when they do, God catches them (Deut. 33:27) and makes them stand again (Rom. 14:4). Even when the elect let go of God's hand, God's hand does not let go of them (Psa. 37:24).

So, the elect will always be saved. Why? Because they were eternally elected by grace (Rom. 8:29-30). Christ loves His bride too much to let her go. He will not lose even a single one of those who were chosen (John 6:39). Rom. 5:9-10 reasons that if Christ loved us enough to die for us, then surely He will do as much to keep us saved (cf. 8:32). Scripture most clearly teaches "once saved, always saved." Salvation has a ratchet effect; it is irrevocable (Rom. 8:1, 11:29; Eccl. 3:14). Furthermore, when the elect are irresistibly drawn to Christ and regenerated by free grace, they are "sealed" by the Holy Spirit as a guarantee that they will always be God's property (Eph. 1:13, 4:30).

Now Scripture also says that one must persevere in faith and obedience to make it to Heaven (Heb. 12:14). Those whose lives are not characterized by this are not saved persons, and they will not make it to Heaven (1 Cor. 6:9; Eph. 5:5). Only those who persevere to the end will be saved (Matt. 10:22, 24:13). But the glory of it all is that the elect most certainly shall persevere to the end (Job 17:9). They will continue in saving faith, for faith is a gift and Christ is the "Author and finisher of our faith" (Heb. 12:2). So, in reality, it is the Perseverance of the Savior.

The true believer has received a new nature in regeneration, and so is not completely bound by the total depravity in which he was first born. This new nature guarantees that he will not (indeed, cannot) live in permanent, perpetual unbelief and disobedience (1 John 3:4-12). Thus, the elect shall bear fruit (Matt. 7:17-18) and shall continue in good works (James 2:14-26). God guarantees that the elect will always eventually repent when they sin (Prov. 24:17). All this is essential to the Fifth Point of Calvinism. The doctrine of eternal security totally excludes the possibility of a regular life of sin for true believers. But the final question is, "How?" The Calvinist answers, "The elect persevere because God perseveres in them." God promised to finish what He began in the elect (Phil. 1:6; Psa. 138:8; 1 Cor. 1:8-9). He will preserve the elect and glorify them in the end (Rom.. 8:30).

Those who "fall away" by apostasy were never saved to begin with. Had they been true Christians, they would have persevered and been preserved (1 John 2:19). This Fifth Point of Calvinism, then, teaches both the preservation and perseverance of the saints by the sovereign grace and power of God.

Conclusion

There have been, of course, many objections against the doctrines of Calvinism. Most of them boil down to two. The first contends that these doctrines are not true, for the reason that God is not totally sovereign. This objection is without foundation, for Scripture repeatedly states that God is sovereign. The second objection is founded on the mistaken notion of Man's "free will". As we have shown, Man is responsible but not free. He is a slave to sin until freed by Christ. Scripture teaches free grace, not free will. Underlying these objections is the secret (and sometimes open) objection, "That's not fair!" This is worst of all, for it is a direct accusation against God. It mistakenly presupposes that Man has rights, when he has none. Man is a guilty, totally depraved enemy of God Almighty. Those who offer these objections would do well to read Rom. 9:20 and Ezek. 18:25.

The Doctrines of Grace

http://www.faithbibleonline.net/biblical-calvinism-by-our-pastor-dr-curt-daniel/