Know therefore that the LORD your God is God, the faithful God who keeps covenant and steadfast love with those who love him and keep his commandments, to a thousand generations, ~ Deuteronomy 7:9 (ESV)

If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. ~ 1 John 1:9 (ESV) 

Let us hold fast the confession of our hope without wavering, for he who promised is faithful. ~ Hebrews 10:23 (ESV)

He who calls you is faithful; he will surely do it. ~ 1 Thessalonians 5:24 (ESV)