John Calvin on Hebrews 4:13

13. Neither is there any creature, etc. The conjunction here, as I think, is causal, and may be rendered for; for in order to confirm this truth, that whatever is hid in man is discerned and judged by God’s word, he draws an argument from the nature of God himself. There is no creature, he says, which is hid from the eyes of God; there is, therefore, nothing so deep in man’s soul, which cannot be drawn forth into light by that word that resembles its own author, for as it is God’s office to search the heart, so he performs this examination by his word.

Interpreters, without considering that God’s word is like a long staff by which he examines and searches what lies deep in our hearts, have strangely perverted this passage; and yet they have not relieved themselves. But all difficulty disappears when we take this view, — that we ought to obey God’s word in sincerity and with cordial affection, because God, who knows our hearts, has assigned to his word the office of penetrating even into our inmost thoughts. The ambiguous meaning of the last words has also led interpreters astray, which they have rendered, “Of whom we speak;” but they ought, on the contrary, to be rendered, With whom we have to do. The meaning is, that it is God who deals with us, or with whom we have a concern; and that, therefore, we ought not to trifle with him as with a mortal man, but that whenever his word is set before us, we ought to tremble, for nothing is hid from him.

Hebrews Chapter 4:14-16

14. Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession.

14. Habentes igitur ponticem magnum qui coelos ingressus est, Iesum filium Dei, teneamus confessionem.

15. For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin.

15. Neque enim habemus pontificem, qui compati non possit infirmitatibus nostris; sed in omnibus tentatum, secundum similitudinem, absque peccato.

16. Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need.

16. Accedamus igitur cum ficucia ad thronum gratiae, ut obtineamus miseericordiam, et gratiam inveniamus in auxilium opportunum.