NEWPORT BEACH, Calif. — For 39 years, the Trinity Broadcasting Network has urged viewers to give generously and reap the Lord’s bounty in return. The prosperity gospel preached by Paul and Janice Crouch, who built a single station into the world’s largest Christian television network, has worked out well for them. Mr. and Mrs. Crouch have his-and-her mansions one street apart in a gated community here, provided by the network using viewer donations and tax-free earnings. But Mrs. Crouch, 74, rarely sleeps in the $5.6 million house with tennis court and pool. She mostly lives in a large company house...