Then I would submit that yhou haven't read it with understanding.
John 6 NASB
35 Jesus said to them, "I am the bread of life ; he who comes to Me will not hunger, and he who believes in Me will never thirst.
36 "But I said to you that you have seen Me, and yet do not believe.
37 "All that the Father gives Me will come to Me, and the one who comes to Me I will certainly not cast out.
38 "For I have come down from heaven, not to do My own will, but the will of Him who sent Me.
39 "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.
40 "For this is the will of My Father, that everyone who beholds the Son and believes in Him will have eternal life, and I Myself will raise him up on the last day."
Jude
24 Now to Him who is able to keep you from stumbling, and to make you stand in the presence of His glory blameless with great joy,
25 to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion and authority, before all time and now and forever. Amen. [Emphasis added]
God's power is able to keep the believer from falling. It is up to Him, not us, to present us before His glorious presence. Our eternal security is a result of God keeping us, not us maintaining our own salvation.
John 10
27 "My sheep hear My voice, and I know them, and they follow Me;
28 and I give eternal life to them, and they will never perish ; and no one will snatch them out of My hand.
29 "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.
30 "I and the Father are one."
Both Jesus and the Father have us firmly grasped in their clasped hands. Who could possibly separate us from the grip of both the Father and the Son? Anticipating your protest, no, we are not able to "crawl out," nor would we want to. Really? Do you want to lose your salvation? What a bogus concept!
Ephesians 1
13 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, 14 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.
Ephesians 4
30 Do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption.
If believers did not have eternal security, the sealing could not truly be unto the day of redemption, but only to the day of sinning, apostasy, or disbelief. Again, the idea of "losing" one's salvation is ludicrous and not biblically supported.
Romans 8
38 For I am convinced that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers,
39 nor height, nor depth, nor any other created thing, will be able to separate us from the love of God, which is in Christ Jesus our Lord.
Our eternal security is based on God's love for those whom He has redeemed. Our eternal security is purchased by Christ, promised by the Father, and sealed by the Holy Spirit. You read passages that speak of perseverance and automatically believe they refer to "doing" right rather than the truth, with is staying on course. Making them about "doing" is a lie of man. They speak, rather, of remaining in a godly life, not to "keep hold" of a salvation you had nothing to do with receiving -- even your "open mind" was opened by the Holy Spirit the day you believed -- but to stay on a course of Christlikeness, first to not be tempted to act as the world and thus make yourself irrelevant to ministry, and two, to actively take part in that ministry. If you live like hell, the world won't notice you are heaven bound.
Again, the "teaching" that one can lose one's salvation is a ludicrous invention of Satan, and must be opposed at every turn.