Why does a monk seclude his life from the world when he can use the love and passion he has for God to preach to others?
Monasticism is a calling from God. A monk's calling is to leave the whole world with its cares and preoccupations and free himself totally to worshipping God. A monk's life is a life of solitude and meditations. This is different from the calling to serve in the world and to preach to others about God. A monk and a preacher (priest/servant) both love the Lord, but each has a different type of calling from God. In Exodus 17:9 we read, "And Moses said to Joshua, 'Choose us some men and go out, fight with Amalek. Tomorrow I will stand on the top of the hill with the rod of God in my hand.'" Moses symbolizes the monks who are praying in the mountains and Joshua symbolizes the priests and servants who are fighting Satan (Amalek) in the world. Please note that both are needed. "And so it was, when Moses held up his hand, that Israel prevailed; and when he let down his hand, Amalek prevailed" (Exodus 17:11).