Isaiah 60:16 - Matthew Poole's English Annotations on the Holy Bible

Thou shalt also suck, & c.; a metaphor taken from children sucking nourishment from the breast. The sense is, that the church should draw or drain the wealth of nations, and the riches and power of kings, and whatever is most excellent, and that it should come freely and affectionately, as milk flows from the breast of the mother; the same thing intended Isaiah 49:23, and in the foregoing verses. Thou shalt know, i.e. experience it; knowing is often put for an experimental knowing. The mighty one of Jacob; styled so either with reference to Jacob's person, he being the first that gave God this title, Genesis 49:24; or with reference to Jacob's posterity, viz. the Jews. These things will certainly be accomplished; for he is the mighty God, and so able; and the God of Jacob, so obliged by covenant and relation.