Genesis 39:5

And it came to pass from the time that he had made him overseer in his house, and over all that he had, that the Lord blessed the Egyptian's house for Joseph's sake; and the blessing of the Lord was upon all that he had in the house and in the field. Not only did Joseph show splendid executive ability, but it is emphatically stated that the blessing of God attended his work, and that Potiphar was blessed by the Lord on account of Joseph. Many a city and country has been blessed by God because of the believers, whose very presence served as a salt and whose prayers kept up the communication with the heavenly Father.