Abraham needed God’s help to father Isaac when he was 100 years old (Gen.21:1-2, Rom.4:19, Heb.11:12). But here, when he is even older, he manages to have six more children without any help from God. (25:2)
Respond: To understand we need to rewind to (Gen 17:2) “And I will make my covenant between me and you, and will make you exceedingly numerous.” The same is written in (Rom 4:19-21) 19 He did not weaken in faith when he considered his own body, which was already as good as dead (for he was about a hundred years old), or when he considered the barrenness of Sarah’s womb. 20 No distrust made him waver concerning the promise of God, but he grew strong in his faith as he gave glory to God, 21 being fully convinced that God was able to do what he had promised. 22 Therefore his faith “was reckoned to him as righteousness.” (Heb 11:12) “12 Therefore from one man, and this one as good as dead, descendants were born, “as many as the stars of heaven and as the innumerable grains of sand by the seashore.” So, when we read (Gen 25:2) it proves the covenant of Almighty God does not falsify but fulfills.