And you shall know the truth. And the truth will set you free

2 Timothy 2:10-13
10 Therefore I endure all things for the sake of the elect, that they also may obtain the salvation which is in Christ Jesus with eternal glory.
11 This is a faithful saying:
For if we died with Him,
We shall also live with Him.
12 If we endure,
We shall also reign with Him.
If we deny Him,
He also will deny us.
13 If we are faithless,
He remains faithful;
He cannot deny Himself.

This is written concerning “those who are chosen, that they may obtain the salvation…” The “chosen” or “elect” always refers to those who are already saved as is clear here. Since all believers, through their position and co-identification with Christ share in his life and death (Rom. 6), they have died with Him and will live with Him. If they endure in this life they will be rewarded and this, includes the promises of reigning with Him as also promised in Rev. 2-3 to the seven churches.
On the other hand, if we deny Him in some way, the point is that He will deny us, not salvation, but as the preceding context shows, He will deny us rewards (see 1 Cor. 3:12). Our faithfulness does not change His faithfulness. He remains faithful for He cannot deny Himself. In His faithfulness, He has promised us eternal life through our union in Him and His finished work. To deny us salvation would be to deny Himself for we are in Him, joined into union with His life.