www.bible.com/100/mat.4.4.nasb1995

It is written. All 3 of Jesus’ replies to the Devil were taken from Deuteronomy. This one, from Dt 8:3 , states that God allowed Israel to hunger, so that He might feed them with manna and teach them to trust Him to provide for them. So the verse is directly applicable to Jesus’ circumstances and a fitting reply to Satan’s temptation. EVERY WORD THAT PROCEEDS OUT OF THE MOUTH OF GOD . A more important source of sustenance than food, it nurtures our spiritual needs in a way that benefits us eternally, rather than merely providing temporal relief from physical hunger.