Abraham was called by God, about 2000 BC, to leave his home in Mesopotamia to journey to Canaan, which was to become known as the Promised Land. The promises God made to him were amazingly wide in scope:
"I will make of thee a great nation, and I will bless thee, and make thy name great... and in thee shall all families of the earth be blessed" (Gen 12:2,3);
"Lift up now thine eyes, and look... for all the land which thou seest, to thee will I give it, and to thy seed for ever" (Gen 13:14,15);
"Look now toward heaven, and tell the stars, if thou be able to number them: and He said unto him, So shall thy seed be" (Gen 15:5).
Abraham's belief in the last of these promises from God was "counted... to him for righteousness", in other words, his sins were forgiven because of his faith (v 6; cf Rom 4:3; Gal 3:6; Jam 2:23).
These promises once again focused on the promised seed, descended from Abraham, eventually revealed as the Lord Jesus Christ (Gal 3:16). The multiplication of that seed "as the stars of heaven" refers to the multitude of people of all ages who would gain salvation through Jesus, by believing the same promises (Dan 12:3; Heb 11:12,13). God endorsed His promises to Abraham by covenants, first a covenant for the land of Israel (Gen 15:18) and then one with his seed, that He would be their God. This was marked in Abraham's natural descendants, the nation of Israel, by the rite of circumcision (Gen 17:1-14). Finally God sealed all of His promises and covenants with a solemn oath: "By Myself have I sworn, saith the LORD... that in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven... and in thy seed shall all the nations of the earth be blessed" (Gen 22:16-18). These promises, subsequently reiterated to Isaac and Jacob (Israel), are the very foundation of the gospel of salvation (Gal 3:8,9). They require that Abraham and all the faithful must rise from the dead, as Jesus did, in order to enjoy them (Acts 24:14,15; 26:6-8).
I hope you have found this helpful.
God bless you,