The warden of the prison could not find fault in anything that was under his [Joseph's] charge, for G-d was with him, and G-d granted him success in whatever he did.
Gen. 39:23
The Torah previously noted that G-d granted Joseph success when he was the servant of Potiphar. But the additional words used in that context – “[G-d granted him success] to his hand” – imply that in his position as Potiphar’s servant, people perceived Joseph’s success as his own accomplishment, attributing it to his good luck.
In contrast, when Joseph was in prison, Joseph was so self-effacing that no one presumed that his success was his own doing. Moreover, the more Joseph was humbled, the more he was blessed with unusual success, since humility makes a person worthy of receiving Divine blessing.
Being a servant is humbling, yet servants retain some sense of self. A prisoner, in contrast, is viewed as an unwanted burden best kept removed from society. Thus, being a prisoner led Joseph to a deeper sense of selflessness and humility than before, making him more worthy of receiving G-d’s blessings.
His success while in prison was therefore much greater than it had been when he was Potiphar’s servant.
Similarly, cultivating selfless devotion to G-d makes us worthy to receive G-d’s blessings for success in all that we do.
--Daily Wisdom Volume 3