That article states:
The doctrine of the āindelible markā attained at ordination to the priesthood seems to have originated in the Scholastic period of the Western Church. This same conception was at times borrowed by Eastern theologians thereafter. The teaching purports the grace of ordination as an indelible irrevocable mark upon the soul of the ordained individual that sets him apart for priestly service analogous to the Levite rank and the priesthood according to the order of Melchizedek in the Old Testament.
The Catchism of the Catholic Church has origin from the time of St. Augustine:
1584 Since it is ultimately Christ who acts and effects salvation through the ordained minister, the unworthiness of the latter does not prevent Christ from acting.76 St. Augustine states this forcefully:
As for the proud minister, he is to be ranked with the devil. Christās gift is not thereby profaned: what flows through him keeps its purity, and what passes through him remains dear and reaches the fertile earth. . . . The spiritual power of the sacrament is indeed comparable to light: those to be enlightened receive it in its purity, and if it should pass through defiled beings, it is not itself defiled.7776 Cf. Council of Trent: DS 1612; DS 1154.
77 St. Augustine, In Jo. ev. 5,15

L 35,1422.