I think I'll just give the Catholic view on this and leave it at that.
From the Council of Trent - decree on Justification
Of this Justification the causes are these:
the final cause indeed is the glory of God and of Jesus Christ, and life everlasting;
while the efficient cause is a merciful God who washes and sanctifies gratuitously, signing, and anointing with the holy Spirit of promise, who is the pledge of our inheritance;
but the meritorious cause is His most beloved only-begotten, our Lord Jesus Christ, who, when we were enemies, for the exceeding charity wherewith he loved us, merited Justification for us by His most holy Passion on the wood of the cross, and made satisfaction for us unto God the Father;
the instrumental cause is the sacrament of baptism, which is the sacrament of faith, without which (faith) no man was ever justified;
lastly, the alone formal cause is the justice of God, not that whereby He Himself is just, but that whereby He maketh us just, that, to wit, with which we being endowed by Him, are renewed in the spirit of our mind, and we are not only reputed, but are truly called, and are, just, receiving justice within us, each one according to his own measure, which the Holy Ghost distributes to every one as He wills, and according to each one's proper disposition and co-operation.