Whether the rite of circumcision was fitting?

Objections

Objection 1 : It seems that the rite of circumcision was unfitting. For circumcision, as stated above (Articles [1],2), was a profession of faith. But faith is in the apprehensive power, whose operations appear mostly in the head. Therefore the sign of circumcision should have been conferred on the head rather than on the virile member.
Objection 2 : Further, in the sacraments we make use of such things as are in more frequent use; for instance, water, which is used for washing, and bread, which we use for nourishment. But, in cutting, we use an iron knife more commonly than a stone knife. Therefore circumcision should not have been performed with a stone knife.
Objection 3 : Further, just as Baptism was instituted as a remedy against original sin, so also was circumcision, as Bede says (Hom. in Circum.). But now Baptism is not put off until the eighth day, lest children should be in danger of loss on account of original sin, if they should die before being baptized. On the other hand, sometimes Baptism is put off until after the eighth day. Therefore the eighth day should not have been fixed for circumcision, but this day should have been anticipated, just as sometimes it was deferred.