Exodus 19:5

if ye will obey

(Cf) (1 Peter 2:9); (Revelation 1:6); (Revelation 5:10). What, under law, was condition, is under grace, freely given to every believer. The "if" of (Exodus 19:5) is the essence of law as a method of divine dealing, and the fundamental reason why "the law made nothing perfect"; (Romans 8:3); (Hebrews 7:18); (Hebrews 7:19).

The Abrahamic: ( See Scofield) - (Genesis 15:18) and New ( See Scofield) - (Hebrews 8:8) covenants minister salvation and assurance because they impose but one condition, faith.