In the opinion of Augustinus Lehmkuhl (Theol. mor., I, nn. 64750) the solemnity of the vow consists in a spiritual consecration, the effect of which is that, after such a vow, a person is irrevocably set apart and appointed by the Church to serve God by the offering of that vow. This opinion has its attractive side, but does it agree with history? The vow of pilgrimage to the Holy Land was temporary and solemn. Or does it agree with the definition of law? Pope Boniface VIII declares those vows to be solemn which are accompanied either by a consecration or by a religious profession. And lastly, does not the consecration logically follow the solemnity, rather than precede or cause it?
In spite of its complication and the forced explanations to which recourse is had, in order to escape from the difficulty, the opinion of Suárez (De religione tr. VII, c.ii, c.x, n.l; c.xii, nn.7-9; c.xiii, nn.3, 8-13; c.xiv, n. 10) still finds distinguished defenders, especially Franz Xavier Wernz (Jus Decretalium, III, n. 572). This opinion places the essence of the solemnity in the absolute surrender of himself by the religious, and the acceptance of that surrender by the religious order, which is accomplished by solemn profession, and also in the incapacity of a person who is bound by solemn vows to perform validly acts that are contrary to those vows; such as the incapacity to possess property, or to contract marriage. This incapacity was not, and is not, always attached to solemn vows, which do involve any particular incapacity; and often solemn vows do not produce this effect. Will they be called solemn as being attached to the vow of obedience, and solemnized by the surrender of oneself?
But, apart from the arbitrary nature of these explanations, the vow of the Crusader was solemn without being attached to any more general vow of obedience; and we have seen that the surrender does not constitute the solemnity. For this reason we prefer a simple opinion, which, in accord with Vasquez (In I-II, Q. xcvi, d. clxv, especially n. 83) and Sanchez (In decalogum, 1, 5, c. 1, n. 11-13), places the material solemnity of vows of religion in the surrender followed by irrevocable acceptance; and with Paul Laymann (De statu religioso, c. i, n. 4), Franciscus Pellizarius (Manuale regularium, tr. IV, c. i. nn. 10-18). Medina (De sacrorum hominum continentia, l. 4, controv. 7, c. xxxviii), V. De Buck (De solemnitate votorum epistola), Nilles (De juridica votorum solemnitate), and Palmieri (Opus theol., II, pp. 445, 446) respects the ordinary juridical signification of the solemn act. The juridical solemnities are formalities to be observed in order to give to the act either its legal value or at least the more or less valuable guarantee of perfect authenticity. This very simple explanation accounts for the historical changes, both those which have reference to the number and conditions of vows, and those which concern their effects. It is natural that there should be greater difficulty in obtaining a dispensation from a solemn vow, and also that the Church should attach certain disabilities to such a vow. But these effects of solemn vows cannot constitute the essence of such vows. However this may be, canon law at the present day does not recognize any vow as solemn except the vow of chastity, solemnized by religious profession in an order strictly so called. The vows taken in religious congregations, like the simple vows which in religious orders precede the solemn profession, and also the complementary simple vows which follow the profession in some institutes, and lastly the final simple vows taken in certain religious orders in place of solemn profession, are, strictly speaking, private; but they derive a certain authenticity from the approval of the Church and the circumstances in which they are taken.