"wherewith the L-rd your G-d has blessed you shall you give him": I might think that if the house were blessed because of him he receives the bestowal; and if not, he does not. It is, therefore, written "Bestow shall you bestow upon him" — in any event. If so, what is the intent of "wherewith the L-rd your G-d has blessed you shall you give him"? The bestowal is in proportion to the blessing.
(Devarim 15:15) "And you shall remember that you were a slave in the land of Egypt": I bestowed upon you (the spoils of Egypt upon your leaving Egypt), and again (at the splitting of the sea) — so, you bestow upon him (once) and then, again. Just as in Egypt I bestowed upon you with a lavish hand, so, you. And thus is it written (Psalms 68:14) "Even for those of you who lie among the sheepfolds, there are wings of a dove sheathed in silver" — the spoils of Egypt. "and its pinions of fine gold" — the spoils of the sea. (Song of Songs 1:11). "Wreaths of gold shall we make for you" — the spoils of the sea; "with spangles of silver" — the spoils of Egypt.