“[The Idolater] feeds on ashes. His deceived mind has led him astray, and he cannot rescue himself, or say, ‘Isn’t there a lie in my right hand’” (Isaiah 44.20)?
Whatever or whoever replaces God in my life are the ashes upon which I feed. People live for money. They live to work. They live for family. They live for country. But money, work, family, or patriotism cannot replace God. If any of those do, I am feeding on ashes.
Ashes do not provide the nutrients I need to continue to physically live. They are not meant to. But this is an obvious metaphor. For instance, I cannot ask a self-help book to provide answers for me. Only the Word of God is the pure milk that helps me grow (1 Peter 2.2). I cannot ask philosophy or people to be what only God is for me. I thirst for God’s presence. My body faints for Him. His faithful love is better than life. He satisfies me as with rich food; my mouth will praise the LORD with joyful lips (Psalm 63.1-5).
This is what Jesus meant in John 6: “Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you. Whoever eats My flesh and drinks My blood has eternal life, and I will raise Him up at the last day. For My flesh is food indeed, and My blood is drink indeed” (John 6.53-55). Obviously, Jesus is utilizing the same sort of metaphor. I can’t feed on ashes; I must feed on Him. This is what faith in Him is all about. To feed on Jesus is to find satisfaction only in His death and resurrection for me (blood and life).