This is one of the most famous and practical pieces of advice in Lal Kitab for Jupiter in the 10th house.
Jupiter is a proud, noble planet (the Guru). But the 10th house belongs to Saturn, the planet of humble, grinding labor. Dr. Sharma warns that if you keep your "Guru-like arrogance" ("Guru ki akad") in your career, you will fail.
You must adopt Saturn's humility. Believe only in your hard work ("karm pe yakeen"). And most importantly, if you are stuck in a difficult situation, swallow your pride. If you have to flatter a fool or call a donkey your father ("gadhe ko bhi baap banaye") to get your work done, do it! Survival and success require absolute humility here.