Genesis 27:33 - The source of all true blessings.

And Isaac trembled very exceedingly, and said, Who? where is he that hath taken venison, and brought it me, and I have eaten of all before thou camest, and have blessed him? yea, and he shall be blessed.

After blessing Jacob, Isaac states yea, and he shall be blessed because all true blessings come only from God. Isaac acknowledges the source of all true blessings in Genesis 28:3.