46 And truly an ordination ceremony, frequent though it be in the Catholic Church, never fails to touch the hearts of those present: how admirable a sight, these young ordinands, who before receiving the subdiaconate, before, that is, consecrating themselves utterly to the service and the worship of God, freely renounce the joys and the pleasures which might rightfully be theirs in another walk of life. We say "freely," for though, after ordination, they are no longer free to contract earthly marriage, nevertheless they advance to ordination itself unconstrained by any law or person, and of their own spontaneous choice!
Source: Ad Catholici Sacerdotii (Vatican.va)