X. Bishops are not to entice or receive the clergy of another diocese.
A cleric from another diocese let no (bishop) accept or invite against the wishes of his own bishop: but only when giver and receiver agree together thereupon by friendly compact. For a man is guilty of a serious injury who ventures either to entice or withhold from a brother's church that which is of great use or high value. And so, if such a thing happen within the province, the metropolitan shall force the deserting cleric to return to his church: but if he has withdrawn himself still further off, he shall be recalled by your authoritative command: so that no occasion be left for either desire of gain or intrigue.
Source: Letters (New Advent)