Scripture emphasizes that preservation leads to perseverence.

John tells us that Jesus Christ, the Good Shepherd, is under promise to his Father (John 6:37-40) and to his sheep directly (John 10:28-29) to keep them so that they never perish. In his high-priestly prayer before his passion Jesus asked that those whom the Father had given him (John 17:2, 6, 9, 24) would be preserved to glory, and it is inconceivable that his prayer, which still continues (Rom. 8:34; Heb. 7:25), will go unanswered.
Paul sees the sovereign plan of God for the salvation of his elect as a unitary whole, of which the glorifying of the justified is part (Rom. 8:29-30). On this basis he builds the triumphant peroration of Romans 8:31-39, in which he celebrates the present and future security of the saints in the almighty love of God. Elsewhere he rejoices in the certainty that God will complete the “good work” that he began in the lives of those Paul addresses (Phil. 1:6; cf. 1 Cor. 1:8-9; 1 Thess. 5:23-24; 2 Thess. 3:3; 2 Tim. 1:12; 4:18). --JI Packer

Good Treatment of a (seemingly) "Eternal Non-Security" Passage

Hebrews 6:4-6 and the Possibility of Apostasy by Sam Storms

Spurgeon Morning June 16

“And I give unto them eternal life; and they shall never perish.”
John 10:28
The Christian should never think or speak lightly of unbelief. For a child of God to mistrust his love, his truth, his faithfulness, must be greatly displeasing to him. How can we ever grieve him by doubting his upholding grace? Christian! it is contrary to every promise of God’s precious Word that thou shouldst ever be forgotten or left to perish. If it could be so, how could he be true who has said, “Can a woman forget her sucking child, that she should not have compassion on the son of her womb? Yea, they may forget, yet will I never forget thee.” What were the value of that promise—“The mountains shall depart, and the hills be removed; but my kindness shall not depart from thee, neither shall the covenant of my peace be removed, saith the Lord that hath mercy on thee.” Where were the truth of Christ’s words—“I give unto my sheep eternal life; and they shall never perish, neither shall any man pluck them out of my hand. My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father’s hand.” Where were the doctrines of grace? They would be all disproved if one child of God should perish. Where were the veracity of God, his honor, his power, his grace, his covenant, his oath, if any of those for whom Christ has died, and who have put their trust in him, should nevertheless be cast away? Banish those unbelieving fears which so dishonor God. Arise, shake thyself from the dust, and put on thy beautiful garments. Remember it is sinful to doubt his Word wherein he has promised thee that thou shalt never perish. Let the eternal life within thee express itself in confident rejoicing.
“The gospel bears my spirit up:
A faithful and unchanging God
Lays the foundation for my hope,
In oaths, and promises, and blood.”

We are not left to our own resources!

Christians can only persevere through the power of God. Left to themselves, to their own strength, to their own resources, they would undoubtedly fall away and lose their salvation. But God will not permit this to happen to those who are his own, whom He has chosen in Christ from the creation of the world (Ephesians 1:4) and whom He predestined to be conformed to the likeness of His Son (Romans 8:29)... this is the heart of the teaching (of perseverence & preservation)... believers persevere only because God in His unchangeable love enables them to persevere.

--Anthony Hoekema

Hymns Help

"My name from the palms of His hands
Etemity will not erase;
Impress'd on His heart it remains,
In marks of indelible grace."

and

"The soul that on Jesus hath leaned for repose,
I will not, I will not desert to his foes;
That soul, though all hell should endeavor to shake,
I'll never, no never, no never forsake!"

Perseverence & Preservation

Let it first be said that in declaring the eternal security of God’s people it is clearer to speak of their preservation than, as is commonly done, of their perseverance. Perseverance means persistence under discouragement and contrary pressure. The assertion that believers persevere in faith and obedience despite everything is true, but the reason is that Jesus Christ through the Spirit persists in preserving them. --J.I. Packer