Sorry, but you are the one who has it backwards.  The sacraments do not exist because of tenets and creeds.  Vatican II revived the 'principle of sacramentality' with regard to the human person.  In the sacraments, it is God's initiative FIRST to us that makes the sacraments efficacious.  The action of the sacraments are FIRST Christ's action which confer grace in and of themselves.  The sacraments do not give grace merely because of the believer's faith, knowledge [Eastern churches baptize, confirms and give the Eucharist to infants].  Likewise, the lack of sanctity in a priest cannot nullify the effectiveness of the sacraments.  The grace of the sacraments is not earned.  Rather, in the sacraments, the believer responds in faith to God's initiative.

Many of these ideas about the sacraments first came out in the Council of Trent.  They were reformulated and up-dated at Vatican Council II.
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A HISTORY OF THE COUNCIL OF TRENT, trans. Ernst Graf, vol. 1 [St.Louis: Herder, 1957].