If someone should come along and say that images teach and instruct lay persons, just as books do scholars, you must answer, "God prohibited images, therefore I intend to learn nothing from them." If someone should come along and say that images remind us of, and recall for us, the suffering of the Lord and often cause someone to pray an "Our Father" and think of God when otherwise he would not pray or think on God, you should reply, "God has prohibited images." Similarly, Christ says that God is spirit. Everyone who truly worships God, prays to God in spirit, Jn. 4:24.
All who worship God through images worship falsehood. They are focusing on the appearance and external signs of God. Yet, their heart is far from God, creating its own idol in the heart and being full of lies, as Isa 44:20 says, "In their foolishness and ignorance they worship them [images], neglecting to say, "I have falsehood in my right hand."
No Christian can deny that spiritual prayer is a divine work which God alone effects. It is written in Jer 33:6, "I will show them the prayer and adoration of peace and truth." That which God alone effects no image ever can. You also must not say that an image of Christ brings you to Christ. For it is eternally true that "no one comes to me unless my Father draw him." All who come to Christ must have learned from God, Jn 6:44. They cannot have been admonished or taught by images to come to Christ. Even if all images on earth were to stand together, they would still not be able to elicit from you as much as a small sigh toward God.—Andreas Rudolff-Bodenstein von Karlstadt, "On the Removal of Images"/The Essential Carlstadt. Translated and edited by E.J. Furcha.