Who here has made popcorn? I ask because this analogy requires that you have such experience. Otherwise I'll have to use a different analogy.
So in the endeavor of popcorn making, first you apply heat to the bottom of the pan and secondly the kernels begin to pop. Heat is the critical item; if you heat too quickly, the kernels will burn. If you heat too slowly, the tiny bit of water in each kernel that is responsible for the popping action will evaporate, and it will never pop. There has to be the right amount of heat applied at the right pace, and then the magic pop, pop, pop!
Teaching and preaching are both like making popcorn. The heat is the instruction, and the kernels are the people, or souls. I could have titled this talk, "Popcorn and Patience," but in the case of people learning something patience and compassion are synonymous, and I happen to favor the term compassion.
There is a verse in the Fifth Canto of the Srimad Bhagavatam wherein Lord Rsabadeva instructs his eldest son that a Guru, or teacher, must patiently give instructions, and not become angry:
SB 5.5.15: If one is serious about going back home, back to Godhead, he must consider the mercy of the Supreme Personality of Godhead the summum bonum and chief aim of life. If he is a father instructing his sons, a spiritual master instructing his disciples, or a king instructing his citizens, he must instruct them as I have advised. Without being angry, he should continue giving instructions, even if his disciple, son or citizen is sometimes unable to follow his order. Ignorant people who engage in pious and impious activities should be engaged in devotional service by all means. They should always avoid fruitive activity. If one puts into the bondage of karmic activity his disciple, son or citizen who is bereft of transcendental vision, how will one profit? It is like leading a blind man to a dark well and causing him to fall in.