ROME — As a clamor builds for Pope Francis to respond to the stunning allegations by his former ambassador in Washington that he covered up abuse and lied about a meeting with a prominent opponent to same-sex marriage, the pontiff has extolled the virtues of silence.

Speaking in a Monday morning homily at the Vatican, Francis said, “With people who don’t have good will, who seek only scandal, who want only division, who seek only destruction — including within the family: silence, prayer.”

He added that “the truth is humble, the truth is silent” and concluded with the prayer, “May the Lord give us the grace to discern when we should speak and when we should stay silent.”

So far, Francis has stuck with silence since the allegations first shook the church on Aug. 26.

Archbishop Carlo Maria Viganò, the former Vatican ambassador, accused the pope of knowing about sexual misconduct by an American cardinal, Theodore E. McCarrick, with adult seminarians years before the abuse became public. Archbishop Viganò also said that Francis lifted sanctions on the cardinal that he claimed had been imposed by his predecessor, Benedict XVI. Those allegations remain unproven.