On Byzantine priests and the sacraments of the “Orthodox”

Thanks for the interest.  The only thing I would mention is that it’s important to understand that heretics and schismatics can have a valid Mass and Eucharist, if they observe proper matter and form and have a valid priesthood.  “Orthodox” schismatics do have a valid Mass, since they have a valid priesthood and employ valid matter and form in their liturgy.  But being outside the Church, they do not profit from the reception of sacraments, but sin when receiving them; and since they are notorious heretics, no Catholic can receive sacraments from them.

Pope Leo XIII, Apostolicae Curae, Sept. 13, 1896: “When anyone has rightly and seriously made use of the due form and the matter requisite for effecting or conferring the sacrament he is considered by that very fact to do what the Church does.  On this principle rests the doctrine that a sacrament is truly conferred by the ministry of one who is a heretic or unbaptized, provided the Catholic rite be employed.  On the other hand, if the rite be changed, with the manifest intention of introducing another rite not approved by the Church, and of rejecting what the Church does, and what by the institution of Christ belongs to the nature of the sacrament, then it is clear that not only is the necessary intention wanting to the sacrament, but that the intention is adverse to and destructive of the sacrament.”

Pope Pius IX, (+1862):“… whoever eats of the Lamb and is not a member of the Church, has profaned.” (Amantissimus # 3)