Tope Koleoso writes about why he shouts when he preaches. Here's an excerpt.
This means that during the sermon, any one of the mentioned emotions, (Anger, Joy or Love), spill out without warning or apology...
Therefore, I shout, I laugh, I cry, and I dance. Therefore, I use my voice, my hands, my legs and my eyes. Therefore, I will do it with utter conviction and passion for if I will not do it from the heart, I will not do it at all...
(via Adrian Warnock)