hereas it is unlawful if
we have vowed to render it. Therefore seemingly it is more pleasing
to God to keep poverty, continence, and obedience without a vow.
Therefore a vow is not requisite for religious perfection.

_On the contrary,_ In the Old Law the Nazareans were consecrated by
vow according to Num. 6:2, "When a man or woman shall make a vow to
be sanctified and will consecrate themselves to the Lord," etc. Now
these were a figure of those "who attain the summit of perfection,"
as a gloss [*Cf. Moral. ii] of Gregory states. Therefore a vow is
requisite for religious perfection.

_I answer that,_ It belongs to religious to be in the state of
perfection, as shown above (Q. 174, A. 5). Now the state of
perfection requires an obligation to whatever belongs to perfection:
and this obligation consists in binding oneself to God by means of a
vow. But it is evident from what has been said (AA. 3, 4, 5) that
poverty, continence, and obedience belong to the perfection of the
Christian life. Consequently the religious state requires that one be
bound to these three by vow. Hence Gregory says (Hom. xx in Ezech.):
"When a man vows to God all his possessions, all his life, all his
knowledge, it is a holocaust"; and afterwards he says that this
refers to those who renounce the present world.

Reply Obj. 1: Our Lord declared that it belongs to the perfection of
life that a man follow Him, not anyhow, but in such a way as not to
turn back. Wherefore He says again (Luke 9:62): "No man putting his
hand to the plough, and looking back, is fit for the kingdom of God."
And though some of His disciples went back, yet when our Lord asked
(John 6:68, 69), "Will you also go away?" Peter answered for the
others: "Lord, to whom shall we go?" Hence Augustine says (De
Consensu Ev. ii, 17) that "as Matthew and Mark relate, Peter and
Andrew followed Him after drawing their boats on to the beach, not as
though they purposed to return, but as following Him at His command."
Now this unwavering following of Christ is made fast by a vow:
wherefore a vow is requisite for religious perfection.

Reply Obj. 2: As Gregory says (Moral. ii) religious perfection
requires that a man give "his whole life" to God. But a man cannot
actually give God his whole life, because that life taken as a whole
is not simultaneous but successive. Hence a man cannot give his whole
life to God otherwise than by the obligation of a vow.

Reply Obj. 3: Among other servic