You said you must endure to the end to be saved. That is not saved now.
I believe regenerated souls WILL persevere and endure to the end, due to the preserving and protecting presence of the indwelling Holy Spirit.
Overcoming and enduring all things is not criteria to be met for salvation, but a promise from God of salvation.
He gives His children faith, holiness, conviction, protections, and great ASSURANCE.
What is the word of truth, the gospel of your salvation and why do you think you need to be "kept"?
The word of Truth is the divine Logos; God Himself come in flesh like His brethren, whose name is Jesus Christ. John 1-14
It was the will of God that I receive the right to be saved and called His child. John 1:12-13
It is His (Hebrew: "chesedh") determinate love for me that keeps me. Psalm 5:7; 13:5