Charles Ellicott Commentary Genesis 28:3

"And God Almighty bless thee, and make thee fruitful, and multiply thee, that thou mayest be a company of peoples." — Genesis 28:3 (ASV)

God Almighty. —Hebrew, El Shaddai. As it was Isaac’s purpose in this blessing to confirm Jacob in the possession of the promises made to Abraham, he is careful to use the same title as that held by God in the covenant by which the land of Canaan was given to his seed, and of which the sacrament of circumcision was the seal. (See Genesis 17:1.)

A multitude of people. —Hebrew, a congregation of peoples. This is not the word used in Genesis 17:4, but one that signifies an assembly, especially one summoned for religious purposes. Like the Greek word for church, ecclesia, it comes from a root signifying “to convoke.” It subsequently became the regular phrase for “the congregation of Israel” (Leviticus 16:17), and implies even here that the nations descended from Jacob would have a religious significance.