When Rabbi David Saperstein was appointed as U.S. ambassador-at-large for international religious freedom in 2014, then-Vice President Joe Biden was the first person to call and congratulate him on the gig.

In that moment and others that followed, Rabbi Saperstein was struck by Biden’s concern for people of faith around the world.

“I know from our conversations how deeply he feels about this issue,” he said.

As president, Biden will have more opportunities to put his passion into action, but also more obstacles in his path.