Council of Chalcedon, Canon VI

Neither presbyter, deacon, nor any of the ecclesiastical order shall be ordained at large, nor unless the person ordained is particularly appointed to a church in a city or village, or to a martyry, or to a monastery.  And if any have been ordained without a charge, the holy Synod decrees, to the reproach of the ordainer, that such an ordination shall be inoperative, and that such shall nowhere be suffered to officiate.

Translation: Henry R. Percival, The Seven Ecumenical Councils, NPNF II.14 (1900), via CCEL.