This quotation from Van Til adds some nuance on the question of whether one must acknowledge God’s existence to be subject to God’s moral law:
After the fall, therefore, all men seek to suppress this truth, fixed in their being about themselves. They are opposed to God. This is the biblical teaching on human depravity. If we are to present the truth of the Christian religion to men we must take them where they are. They are: a) creatures made in God’s image, surrounded by a world that reveals in its every fact God’s power and divinity. Their antithesis to God can never be metaphysical. They can never be anything but image bearers of God. They can never escape facing God in the universe about them in their own constitution. Their antithesis to God is therefore an ethical one; b) because of God’s common grace, this ethical antithesis to God on the part of the sinner is restrained, and thereby the creative forces of man receive the opportunity of constructive effort. In this world the sinner does many ‘good’ things. He is honest. He helps to alleviate the sufferings of his fellow men. He ‘keeps’ the moral law. Therefore the ‘antithesis’ besides being ethical rather than metaphysical, is limited in a second way. It is one of principle, not one of full expression. If the natural man fully expressed himself as he is in terms of the principle of ethical hostility to God that dwells in his soul, he would be a veritable devil. Obviously he is nothing of the sort. He is not at all as ‘bad as he may be.’
Strange, Daniel; Strange, Daniel (2015-02-03). Their Rock Is Not Like Our Rock: A Theology of Religions (p. 92). Zondervan. Kindle Edition. Quoting: Van Til, Introduction to Systematic Theology, p. 45. (By the way, I am finding Dr. Daniel Strange’s book quite useful.