The supreme task which Christ had to fulfill was his priestly work of atonement which he completed as mediator between God and man. By the union in himself of humanity and divinity Christ is by nature the mediator. As a man from among men, Christ is our mediator with the Father; yet he is also capable of offering a worthy sacrifice to God because, by virtue of the union of his human nature with the Second Person of the Godhead, his human actions have in infinite value. In this fullest sense, the priesthood belongs to Christ alone.
The degrees of order - the four minor and three major orders with the highest of all, that of Bishop - signify an order of rank in the mediation of grace. It must be distinguished from the other order of rank which concerns jurisdiction, magisterium and pastorate. The latter are not essentially linked with the powers of mediation of grace, but in the concrete order established by God there are close relationships between the two kinds of power. For example, the fact that the power of forgiving sins exists in the Church does not, in itself, say anything about who has this power. But in the divine order, only a priest can have it.
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