וְאֵ֤ל שַׁדַּי֙ יְבָרֵ֣ךְ אֹֽתְךָ֔ וְיַפְרְךָ֖ וְיַרְבֶּ֑ךָ וְהָיִ֖יתָ לִקְהַ֥ל עַמִּֽים׃
And God Almighty bless thee, and make thee fruitful, and multiply thee, that thou mayest be a congregation of peoples;
Rashi on Genesis
ואל שדי AND GOD ALMIGHTY —He who has a sufficiency of blessings שָׁדִּי for those who are blessed by Him, יברך אתך MAY HE BLESS THEE.
Siftei Chakhamim
He who has sufficient blessings... Otherwise, why is this particular Name of Hashem mentioned here?