President Joe Biden has urged supporters to stay unified behind him at a rousing Black church service Sunday where the pastor referenced biblical teachings in declaring “never count Joseph out,” and blamed jealousy for intensifying pressure from some Democrats to abandon his reelection bid. Speaking from a stage Sunday flanked by sunshine from a pair of stained-glass windows at Mount Airy Church of God in Christ in northwest Philadelphia, the 81-year-old Biden declared: “I honest to God, have never been more optimistic about America’s future if we stick together.” He has vowed to remain in the presidential race despite more Democrats calling for him to step aside.