With the Eucharist, as with other aspects of theology, Anglicans are largely directed by the principle of "lex orandi, lex credendi" which means "the law of prayer is the law of belief". In other words, sacramental theology as it pertains to the Eucharist is sufficiently and fully articulated by the Book of Common Prayer of a given jurisdiction. As defined by the 16th-century Anglican theologian Richard Hooker, the sacraments are said to be "visible signs of invisible grace"; similarly the "Catechism" of the 1662 version states that a sacrament is "an outward and visible sign of an inward and spiritual grace given to us, ordained by Christ himself, as a means whereby we receive the same, and a pledge to assure us thereof." It thus has the effect of conveying sanctification in the individual participating in the sacrament. According to this, in the Eucharist the outward and visible sign is "bread and wine" and the "thing signified", the "body and blood of Christ", which are truly taken and received by the faithful in the Lord's supper.