I've been slowly working my way through Luther's Bondage of the Will, which sadly I've never taken the time to read until now. It's brilliant and stirring. In the below section, Luther addresses Erasmus' admonition that it is impious to speculate on the meaning and dimensions of God's omnipresence. Acknowledging abuses by skeptics, Luther blasts Erasmus for cloaking the power and beauty of this doctrine through a veil of false piety. Rather, omnipresence is a great comfort to the Christian at all times as it is laid out in Scripture.
Luther's doctrine of omnipresence certainly depends on recognizing the tender love of God revealed in Christ. As it will be obvious in the below text, an omnipresence shaped by the Gospel of Christ looks remarkably different than what one finds among moralist preachers of Pietistic and Revivalist stripe. God's all-presence is not a Big Other looking, observing, and judging. Rather, God's presence is peace and security to the Christian, who knows His true face. While this is certainly not painless or easy, this is not the overbearing presence of the Other, but the power of the Savior, who restores, rebuilds, and liberates. Here is Luther at his best, revealing the power of the Gospel in all places and at all times:
"NOR are you right in the use of this example; nor in condemning the discussion of this subject before the multitude, as useless — that God is in a beetle’s hole and even in a sink! For your thoughts concerning God are too human. I confess indeed, that there are certain fantastical preachers, who, not from any religion, or fear of God, but from a desire of vain-glory, or from a thirst after some novelty, or from impatience of silence, prate and trifle in the lightest manner. But such please neither God nor men, although they assert that God is in the Heaven of Heavens. But when there are grave and pious preachers, who teach in modest, pure, and sound words; they, without any danger, nay, unto much profit, speak on such a subject before the multitude.
Is it not the duty of us all to teach, that the Son of God was in the womb of the Virgin, and proceeded forth from her belly? And in what does the human belly differ from any other unclean place? Who, moreover, may not describe it in filthy and shameless terms? But such persons we justly condemn; because, there are numberless pure words, in which we speak of that necessary subject, even with decency and grace. The body also of Christ Himself was human, like ours. Than which body, what is more filthy? But shall we, therefore, not say what Paul saith, that God dwelt in it bodily? (Col. ii. 9.) What is more unclean than death? What more horrible than hell? Yet the prophet glorieth that God was with him in death, and left him not, in hell. (Ps. xvi. 10, Ps. cxxxix. 8.).
The pious mind, therefore, is not shocked at hearing that God was in death and in hell: each of which is more horrible, and more loathsome, than either a hole or a sink. Nay, since the Scripture testifies that God is every where, and fills all things, such a mind, not only says that He is in those places, but will, of necessity learn and know that He is there. Unless we are to suppose that if I should at any time be taken and cast into a prison or a sink, (which has happened to many saints,) I could not there call upon God, or believe that He was present with me, until I should come into some ornamented church. If you teach us that we are thus to trifle concerning God, and if you are thus offended at the places of His essential presence, by and by you will not even allow that He dwells with us in Heaven. Whereas, “the Heaven of Heavens cannot contain Him,” (1 Kings viii. 27.); or, they are not worthy. But, as I said before, you, according to your custom, thus maliciously point your sting at our cause, that you may disparage and render if hateful, because you find it stands against you insuperable, and invincible."