At some points in Life, God places you to be in some certain places, to prepare your way into the future. Nothing happens as a co-incidence when God's involved. That's why one needs to be sure of His will. Joseph was sold to be a slave in Potiphar's house, a place where the potiphar's wife of this world is ordained to lure and tempt Joseph, so he may get imprisoned. There he met his destiny forerunner, the Mr Butler whom he foretold his future by interpreting his dream. And later on, he announced him,and there comes the promotion. Challenges are necessary, you must face it but by His grace.