Representing God through images was forbidden so that people would not begin to think that God had the form of a creature or that He was an object. The commandment was for the people’s own good, so that they not condemn themselves by mistakenly adoring a thing instead of God. In other words, what is unacceptable is to turn to material objects and put in them the full confidence that we owe to the one, living and true God. He is not a material being, but a spiritual reality. This is why the people must not adore material representations of the true God either: because there is the risk of confusing the true God with the image that represents Him and come to believe that He is a material God.
And why is it that Catholic images have existed in the past and will continue to exist in the future?
What many people don’t realize is that, in addition to the prohibition against making images (and now we know why), there is also an Old Testament permission to make images.
We should keep in mind that the prohibition refers directly to adoring images, not to the simple fact of making them, as long as they function only as a sign of God’s presence. In this sense, God commands things, objects and images to be made. Such is the case of the Ark of the Covenant, with its golden cherubim and with a mercy seat also of pure gold (Exodus 25:10-22). These elements are not worthy of divine honors, and they cannot be worshipped as if they were God.
But the people needed and still need these outward signs that reach us through our senses. God commanded this to be built as a sign of his presence among his people. People went to the Ark of the Covenant to pray because it was the symbol of God’s presence (Joshua 7:6). Further proof of all of this is that the very meeting tent was built by divine command and was full of images, just as the Temple of Jerusalem was. It is clear that they were not violating the prohibition issued by God.
Another example? God ordered Moses to make a bronze serpent: “Make a poisonous serpent, and set it on a pole [Jesus himself considers this bronze serpent as a symbol of himself]; and everyone who is bitten shall look at it and live” (Numbers 21:6-9). Naturally, it’s not the case that this bronze serpent had any special power that could raise it to the rank of divinity. Turning to it was an act of faith and confidence in the Word that God had spoken to them. Later on, when the people strayed from this intention and started to worship it, Hezekiah ordered it destroyed (2 Kings 18:4).
The Bible texts that prohibit making images are for the people of the Old Testament, due to the risk they ran of falling into idolatry like the neighboring nations who adored idols as if they were gods. The texts of the New Testament that speak of idols refer to authentic idols adored by pagans, not to simple images. This is why the Second Ecumenical Council of Nicaea in 787 “justified … the veneration of icons” (Catechism of the Catholic Church, 2131).
The God of the Old Testament had no body, and was invisible. He could not be represented by images. But from the moment that God revealed himself in human form, Christ became “the image of the invisible God,” as Saint Paul said (Colossians 1:15); and yes, they saw him and touched him. This means that, in the New Testament, the permission for images representing the Godhead took on a new character because of the Incarnation of the Son of God.
God continues to be purely spiritual, but he has become intimately united to a human nature, which is material. Therefore, it is logical that we represent him visually to worship him (Catechism of the Catholic Church, 1159 and following, 2129 and following). The representation of Christ in images is completely licit, since they are the representation of someone who really is God. Hence, when we worship Jesus, looking at an image of him, we do not adore the materiality of the image, but rather the Divine Person who is represented therein. And by looking, for example, at an image of Christ Crucified, we remember how much he suffered for us and we feel moved to love him more and trust in him more.