Albert Barnes Commentary Isaiah 29:15

"Woe unto them that hide deep their counsel from Jehovah, and whose works are in the dark, and that say, Who seeth us? and who knoweth us?" — Isaiah 29:15 (ASV)

Woe unto them that seek deep ... - (Isaiah 29:15) That is, who attempt to conceal their “real” intentions under a plausible exterior, and correct outward deportment. This is most strikingly descriptive of the character of a hypocrite who seeks to conceal his plans and his purposes from the eyes of people and of God. His external conduct is fair; his observance of the duties of religion exemplary; his attendance on the means of grace and the worship of God regular; his professions loud and constant, but the whole design is to “conceal” his real sentiments, and to accomplish some sinister and wicked purpose by it.

From the Lord - This proves that the design of the hypocrite is not always to attempt to deceive other people, but that he also aims to deceive God.