And his master saw that the LORD was with him, and that the LORD made all that he did to prosper in his hand.

Jamieson-Fausset-Brown Bible Commentary

3. his master saw that the Lord was with him-Though changed in condition, Joseph was not changed in spirit; though stripped of the gaudy coat that had adorned his person, he had not lost the moral graces that distinguished his character; though separated from his father on earth, he still lived in communion with his Father in heaven; though in the house of an idolater, he continued a worshipper of the true God.

Matthew Henry's Concise Commentary

39:1-6 Our enemies may strip us of outward distinctions and ornaments; but wisdom and grace cannot be taken from us. They may separate us from friends, relatives, and country; but they cannot take from us the presence of the Lord. They may shut us from outward blessings, rob us of liberty, and confine us in dungeons; but they cannot shut us out from communion with God, from the throne of grace, or take from us the blessings of salvation. Joseph was blessed, wonderfully blessed, even in the house where he was a slave. God's presence with us, makes all we do prosperous. Good men are the blessings of the place where they live; good servants may be so, though mean and lightly esteemed. The prosperity of the wicked is, one way or other, for the sake of the godly. Here was a wicked family blessed for the sake of one good servant in it.