77 This purchase, however, does not immediately have its full effect; since Christ, after redeeming the world at the lavish cost of His own blood, still must come into complete possession of the souls of men. Wherefore, that the redemption and salvation of each person and of future generations unto the end of time may be effectively accomplished, and be acceptable to God, it is necessary that-men should individually come into vital contact with the sacrifice of the cross, so that the merits, which flow from it, should be imparted to them. In a certain sense it can be said that on Calvary Christ built a font of purification and salvation which He filled with the blood He shed; but if men do not bathe in it and there wash away the stains of their iniquities, they can never be purified and saved.
Source: Mediator Dei (Vatican.va)