And you shall be to Me a kingdom of priests and a holy nation Set apart for My purpose.’ These are the words that you shall speak to the Descendants of Abraham.” Exodus 19:6
This is called a Messianic Promise and Covenant. This was written to a Future Generation before they were born and that is you and me. Predestined to be conformed into the Image of His Son the Messiah.
Romans 8:29
29 For those whom He Foreknew and loved and Chose Beforehand, He also Predestined to be Conformed to the Image of His Son and Ultimately share in His complete Sanctification, so that He would be the firstborn (the Seed) most beloved and honored among many Believers.