So according to you Abraham was saved by grace but at the same time he had to do works to be saved. But that idea is contradicted by what Paul wrote about Abraham here:
"What shall we say then that Abraham our father, as pertaining to the flesh, hath found? For if Abraham were justified by works, he hath whereof to glory; but not before God. For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness. Now to him that worketh is the reward not reckoned of grace, but of debt" (Ro.4:1-4).
Paul
Rom 4:2 For if Abraham was justified by works, he has something to boast about, but not before God.
agrees with this covenant which was by faith
Gen 15:5 And he brought him outside and said, "Look toward heaven, and number the stars, if you are able to number them." Then he said to him, "So shall your offspring be."
Gen 15:6 And he believed the LORD, and he counted it to him as righteousness.
and
Jas 2:21 Was not Abraham our father justified by works when he offered up his son Isaac on the altar?
agrees with this covenant which has works
Gen 17:10 This is my covenant, which you shall keep, between me and you and your offspring after you: Every male among you shall be circumcised.
Gen 17:14 Any uncircumcised male who is not circumcised in the flesh of his foreskin shall be cut off from his people; he has broken my covenant."