...but our faith is not the cause of our eternal salvation...
The Brazen Serpent -- which Moses set up on a pole in the wilderness -- is a type of Christ. Those Israelites had to LOOK UPON (gaze steadily upon) that Serpent in order to be saved from instantaneous death.
Every sinner must LOOK UPON CHRIST IN GENUINE FAITH in order to be saved by grace. Thus we have this Scripture: For by GRACE are ye saved THROUGH FAITH... (Eph 2:8)
When a sinner (a) believes God, (b) believes the record that God had given us concerning His Son, (c) believes with all his/her heart that Jesus is indeed the Son of God, God manifest in the flesh, (d) believes with all his/her heart that Christ died for our sins according to the Scriptures, and rose again the third day according to the Scriptures for our justification, God takes that faith into account and imputes righteousness to the one who believes God. Just as Abraham believed God, and it was imputed/accounted to him for righteousness. And this is all BECAUSE OF GOD'S GRACE.
This grace has come to earth for all mankind, not just the so-called "elect".
TITUS 2
11 For the grace of God that bringeth salvation hath appeared to all men,
12 Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world;
13 Looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ;