In this thread about TR and spirituality, I would be remiss not to mention Grace Reformed Church, on 16th Street in Washington, D.C. This is the church that TR attended. His pew is still there. According to a church brochure, which I picked up on a visit last fall:

Mr. Roosevelt took part earnestly in all of the services, singing every hymn with enthusiasm, and listening most intently to the sermon with his eyes never leaving the pastor. … In addition, he sent flowers from the White House greenhouse every Saturday for Sunday’s worship service.