If God is able to save us He is surely able to keep us, a truth taught even in the OT "The Lord will protect you from all evil. He will keep your soul." (Ps 121:7). Jesus warned Peter that "Satan has demanded permission to sift you like wheat; but I have prayed for you, that your faith may not fail; and you, when once you have turned again, strengthen your brothers" (Lk 22:31,32). Soon after Jesus said that, Peter denying Christ three times but later he repented and was restored to Christ and to useful service, just as our Lord had prayed. I believe Jesus declaration is very clear on this issue of eternal security in (Jn 6:37, 38, 39) in which He said “All that the Father gives Me shall come to Me, and the one who comes to Me I will certainly not cast out. "For I have come down from heaven, not to do My own will, but the will of Him who sent Me. And this is the will of Him who sent Me, that of all that He has given Me I lose nothing, but raise it up on the last day. ” God’s will indeed will be done. Jesus later said, “I give eternal life to them [those who follow Him]; and they shall never perish, and no one shall 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” (John 10:28, 29). It is God Who provides salvation and God Who preserves it. I believe Paul teaches on eternal security in Eph 1:13,14 where he writes that “In Him, you also, after listening to the message of truth, the gospel of your salvation having also believed, you were sealed in Him with the Holy Spirit of promise, Who is given as a pledge of our inheritance, with a view to the redemption of God's own possession, to the praise of His glory." Further Paul encourages all believers through the ages that we are secure in Christ because "He who began a good work in you will perfect it until the day of Christ Jesus." (Php 1:6). I believe Peter also echoes the truth of eternal security in (1Pe 1:5) in which he emphasizes that believers "are protected by the power of God through faith for a salvation ready to be revealed in the last time." A number of passages link the act of believing with “eternal life” (John 3:36, 5:24; 6:47; 10:28; 1Jn 5:13) and if God means what He says, that the life they receive is indeed eternal, then logically this new life lasts forever. To say that "eternal life" can be lost or does not last forever is to argue with the plain sense of what God states. I fear however that some people wrongfully conclude that "once saved always saved" is license to do anything one wants to once they are "saved". But short of a radical change in one's behavior and a holding fast to the end, I believe that these people were most likely never saved at the inception. So they could hardly lose what they never had. So many famous modern day "converts" have fallen back into their sinful lifestyles which has led some to use this as evidence that one can lose his or her salvation. But I believe that only those individuals who endure to the end were ever truly saved. James clearly links genuine salvation with good works, not saying that the "good works" save a person but that a person who is truly saved will be shown to be saved by those works. (see Jas 2:14, 15, 16, 17s, Jas 2:18, 19, 20s, Jas 2:21, 22, 23s, Jas 2:24, 25, 26s). Eternal security is only eternally secure if it reflects genuine salvation and thus the entire epistle of first John is written that we might clearly see the distinguishing marks of a true believer (1John 5:11). For example John writes that "Everyone who practices (present tense = as their lifestyle, the habit of their life) sin also practices (present tense = as their lifestyle, the habit of their life) lawlessness; and sin is lawlessness. And you know that He appeared in order to take away sins; and in Him there is no sin. No one who abides in Him sins; no one who sins (present tense = as their lifestyle, the habit of their life) has seen Him or knows Him. Little children, let no one deceive you; the one who practices (present tense = as their lifestyle, the habit of their life) righteousness is righteous, just as He is righteous; the one who practices (present tense = as their lifestyle, the habit of their life) sin is of the devil; for the devil has sinned from the beginning. The Son of God appeared for this purpose, that He might destroy the works of the devil. No one who is born of God practices (present tense = as their lifestyle, the habit of their life) sin, because His seed abides in him; and he cannot (present tense = as their lifestyle, the habit of their life) sin, because he is born of God. By this the children of God and the children of the devil are obvious: anyone who does not practice (present tense = as their lifestyle, the habit of their life) righteousness is not of God, nor the one who does not love his brother." (1Jn 3:4, 5, 6, 7, 8, 9, 10, cp Paul's not too subtle warnings to stop being deceived in Gal 5:21s = where "practice" = present tense = as their lifestyle, 1Cor 6:9, cp Eph 5:5, 6s). The apostle John could not have been much clearer regarding what constitutes genuine salvation. Many will still be deceived thinking that they can pray a prayer to receive Jesus and yet never have a change in their life and continue living their life just as they did before they prayed the prayer. Jesus sternly warned that "Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven; but he who does (present tense = as their lifestyle) the will of My Father who is in heaven. Many will say to Me on that day, 'Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?' And then I will declare to them, 'I never knew you; DEPART (present imperative = command in the continuous mood, continually depart from Him) FROM ME, YOU WHO PRACTICE (present tense = as their lifestyle) LAWLESSNESS.' (Mt 7:21, 22, 23s).