Biden, a devout Catholic and the second to take the presidency, is starting Inauguration Day with Mass at the Cathedral of St. Matthew the Apostle in Washington, joined by the top congressional leaders.

House Speaker Nancy Pelosi — another devout Catholic — outgoing Senate Majority Leader Mitch McConnell, Senate Minority Leader Chuck Schumer and House Minority Leader Kevin McCarthy joined Biden for the service, along with his wife, Jill Biden, Vice President-elect Kamala Harris and her husband Doug Emhoff — the nation’s first second gentlemen — Biden extended invitations to top congressional leaders. In a show of unity, all accepted those invites.

Joint Congressional Committee on Inaugural Ceremonies Chairs Sen. Amy Klobuchar, D-Minn., and House Majority Leader Steny Hoyer, D-Md., were also in attendance.

Faith has played a significant role in Biden’s life — when he lost his wife Neilia and young daughter Naomi in a horrific 1972 car accident in which his young sons Beau and Hunter were severely injured. Beau died of a brain tumor in 2015 at age 46.

An Irish violinist will play and soprano Renee Fleming will sing “On Eagle’s Wings” – the Catholic hymn Biden said his son loved and which he quoted from in his November victory speech.