Charles Ellicott Commentary 1 Kings 17:15

"And she went and did according to the saying of Elijah: and she, and he, and her house, did eat [many] days." — 1 Kings 17:15 (ASV)

The barrel of meal wasted not. —The miracle is doubly remarkable:

1. In this instance, as in the similar miracles of Elisha and of our Lord Himself, we see that God’s higher laws of miracle, like the ordinary laws of His providence, admit within their scope the supply of what we should consider as homely and trivial needs—in this respect perhaps contradicting what our expectation would have suggested.
2. It is a miracle of multiplication, which is virtual creation—not necessarily out of nothing—doing rapidly and directly what, under ordinary laws, has to be done slowly and by indirect process.