Jesus is faithful
Jude “24 To him who is able to keep you from stumbling and to present you before his glorious presence without fault and with great joy— 25 to the only God our Savior be glory, majesty, power and authority, through Jesus Christ our Lord, before all ages, now and forevermore! Amen.”

We cannot be faithful on our own.
But Jesus is faithful.
He is faithful even to the faithless.
The faith of a mustard seed saves us.
The believer may struggle with unbelief at times saying “Lord I believe, but help me with my unbelief”

But Jesus is faithful. God is faithful.
He is the One who does it.

1 Thess 5 “23 May God himself, the God of peace, sanctify you through and through. May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ. 24 The one who calls you is faithful, and he will do it.”