A name is more than a mere label; it captures a person's essence and destiny. The moment a pioneer of faith steps into a new covenant, his very identity must evolve to match his elevated spiritual reality. This moment marks a profound turning point in the patriarch's life. As he enters the covenant of circumcision, God changes his name, granting him a new essence and mastery over his body and future. This is not just an update to a title, but a complete uprooting of his past. Unlike Jacob, whose original name remained in use alongside his new name, the old name here is entirely retired. Some explain that the original name was given while he lived among the nations, before he was circumcised and brought into the covenant. Therefore, it had to be completely abandoned so as not to recall his past [ריב״א, חזקוני]. Still, the primary approach among commentators is that his original name was not derogatory. Rather, it carried dignity, meaning either the father of his native land or an exalted father. The instruction to stop using the old name is directed primarily at his descendants, though the rest of the world might continue to use it [העמק דבר]. The new name was established to become a permanent fixture in the mouths of future generations, immortalizing the miracle God performed for him [רד״ק].
The new name represents a profound enhancement of his former identity. The addition of a new letter to his name symbolizes the power of procreation and fertility that God now grants him [רבנו בחיי, שפתי כהן]. According to early sages, his original destiny dictated that he would remain childless, but his new identity is one capable of having children. Although he had already fathered Ishmael under his old name, the primary and most significant birth of his spiritual lineage will come through Isaac. Bringing about this lineage requires a fundamental change in both his essence and that of his wife [אור החיים].
The core meaning of his new identity is rooted in his destiny as the father of a multitude of nations. The new name functions as a contraction meaning exactly that—a mighty father to a massive gathering of people [אבן עזרא, שד״ל, ביאור יש״ר]. One might wonder why a specific letter from his old name was not removed to make the new name a perfect phonetic match for this phrase. The accepted answer is that God did not want to diminish any part of his original name. Every original letter was kept in place so that none would feel slighted by its removal, similar to what happened when a letter was removed from his wife's original name [רש״י, מזרחי].
Through this change, his destiny takes on a universal scale. He becomes the spiritual father of all humanity, much like the first man. God endows him with numerous virtues in his relationship with both the world and the Divine, characterizing him as a father, a chosen one, beloved, a king, a veteran, and a faithful servant [תורה תמימה]. Because he is established as the father of all nations, Jewish law dictates that converts are considered his direct children. They are permitted to bring first fruits and pray to God using the phrase "God of our fathers," as their spiritual lineage traces directly back to him [תורה תמימה]. Finally, this grand destiny is not merely a promise for the distant future. It is a spiritual reality that takes effect immediately, transforming his standing in the world from that very day onward [ספורנו].