Thomas Ridgley on the unlawfulness of representing any of the Persons in the Godhead

It must be inquired whether it be unlawful to represent any of the persons in the Godhead, by pictures or carved images? We answer, that, God being infinite and incomprehensible, it is impossible to frame any image like him. [Isaiah 40:18; 46:5; Acts 17:29] Moreover, he assigns as a reason why Israel should make no image of him, that 'they saw no manner of similitude when he spake to them in Horeb, out of the midst of the fire;' and adds, 'lest ye corrupt yourselves, and make you a graven image.' [Deuteronomy 4:15, 16] And the apostle styles the representing of God by an image, an offering the highest affront to him, when he speaks of some who 'changed the glory of the uncorruptible God into an image made like to corruptible man.' [Romans 1:23] But there are some who, though they do not much care to defend the practice of making pictures of God, yet plead for describing an emblem of the Trinity, such as a triangle, with the name Jehovah in the midst of it. Now, I would observe concerning this practice, that if the design of it be to worship God by the emblem, it is idolatry; but if not, it is unwarrantable, and, indeed, unnecessary; since a Trinity of persons in the unity of the divine essence, is to be understood as revealed in scripture, and not brought to our remembrance by an emblem, which is an ordinance of our own invention. It is farther inquired whether we may not describe our Saviour, as he sometimes is by the Papists, in those things which respect his human nature? whether we may not portray him as an infant in his mother's arms, or as conversing on earth, or hanging on the cross? The Papists not only describe him thus, but adore the image or representation of Christ crucified, which they call a crucifix. But whatever of Christ comes within the reach of the art of man to delineate or describe, is only his human nature, which is not the object of divine adoration; so that the practice of describing him in the way mentioned tends rather to debase, than to give us raised and becoming conceptions of him as such.

~Thomas Ridgley, A Body of Divinity, wherein the doctrines of the Christian religion are explained and defended: being the substance of several lectures on the Assembly's Larger catechism