This delightful loop gets its engine running the moment you gain any initial bit of life, kickstarted and amplified by Cleric Class's replacement effect which permanently boosts your life gains. That extra life triggers Cleric Class's level 2 ability to drop a +1/+1 counter onto Herd Baloth, which in turn answers the call by spawning a 4/4 green Beast creature token. Every time that token (or any other creature) enters the battlefield, Answered Prayers triggers to grant you life—which safely loops right back into Cleric Class to keep the cascade of counters and tokens flowing endlessly.