The Torah tells us that throughout Yossef's term of service in Potifar's house, "God was with him, and he was successful" (39:2). This verse is usually understood as a cause and effect: because God was with him - meaning, He helped him -, Yossef had success. The Chafetz Chayim, however, reads the verse as follows: "God was with him, despite the fact that he was successful." Although success often leads one to forget his total dependence on the Almighty, this did not happen to Yossef. God remained with him, in his mind and heart, even as he rose through the ranks in Potifar's home.
The Chafetz Chayim adds in this context an insightful comment regarding the special prayer recited on "Shabbat Mevarchim" (Shabbat before Rosh Chodesh, such as this coming Shabbat). Twice in this prayer we beseech God for "yirat Shamayim" (fear of Heaven): "lives that have within them fear of God… lives that we should have love of Torah and fear of Heaven." The Chafetz Chayim explains than an additional petition for fear of Heaven becomes necessary after the request we submit in between these two clauses: "lives of wealth and honor." All too often material prosperity and high social ranking steer one away from Torah study and fear of Heaven. We therefore pray for the power of Yossef, the ability to retain our genuine love for God and His Torah, even when success threatens to blind us from our religious obligations.