God's promise and the prayer of Faith
God renews his promise to Jacob, the ancestor of the twelve tribes of Israel. Before confronting his elder brother Esau, Jacob wrestles all night with a mysterious figure who refuses to reveal his name, but he blesses him before leaving him at dawn. From this account, the spiritual tradition of the Church has retained the symbol of prayer as a battle of faith and as the triumph of perseverance.
Source: Catechism of the Catholic Church (Vatican.va)