72 The chief responsibility, however, rests with the Bishop, who according to the severe law of the Church "should not confer holy orders on anyone, unless from positive signs he is morally certain of canonical fitness; otherwise he not only sins grievously, but also places himself in danger of sharing in the sins of others." This canon is a clear echo of the warning of the Apostle to Timothy: "Impose not hands lightly on any man, neither be partaker of other men's sins." "To impose hands lightly," Our Predecessor St. Leo the Great expounds, "is to confer the sacerdotal dignity on persons not sufficiently approved: before maturity in age, before merit of obedience, before a time of testing, before trail of knowledge; and to be a partaker of other men's sins is for the ordainer to become as unworthy as the unworthy man whom he ordains"; for as St. John Chrysostom says, "You who have conferred the dignity upon him must take the responsibility of both his past and his future sins."
Source: Ad Catholici Sacerdotii (Vatican.va)