Rua attended a school that the Brothers of the Christian Schools managed. It was not long following this that he met Giovanni Bosco who was working to improve the lives of the children of the neighborhood and who had just built his "oratorio" (oratory) of Francis de Sales in Valdocco. Rua was among the first with whom Bosco had shared his idea of founding a religious congregation and he joined the "oratorio" on 22 September 1852 to finish his education. One morning in 1847 Bosco was handing medals to passing children and extended his open left hand to Rua and made the gesture with his other hand of cutting the left in half and offering it to Rua. Bosco said to "take it!" but Rua said: "But take what?" No response was given until sometime later when Bosco told Rua that their lives were intertwined into doing the work of God. Bosco also sent him to Saint Giuseppe Cafasso for spiritual guidance.