As I boarded the airplane to study in a city a thousand miles from home, I felt nervous and alone. But during the flight, I remembered how Jesus promised His disciples the comforting presence of the Holy Spirit.

Jesus’s friends must have felt bewildered when He told them, “It is for your good that I am going away” (John 16:7). How could they who witnessed His miracles and learned from His teaching be better off without Him? But Jesus told them that if He left, then the Advocate—the Holy Spirit—would come.

After Jesus and His friends ate their last supper together, they…