Theory and practice of the confessional by Caspar Erich Schieler, Richard Frederick Clarke
Then the priest goes on to reconcile the penitent to the Church by the removal of all censures which close the door to the Sacraments and other means of grace. This absolution from censure should always precede that of the sins as a measure of precaution even when no sins involving censure have been confessed. The Church insists on this, and many moralists teach that the confessor by omitting this absolutio a censuris would commit a venial sin by his disobedience to the command of the Church. Even in cases of the most pressing urgency the priest should use the form: Ego te absolvo ab omnibus censuris el peccatis in nomine Patris, etc. St. Alphonsus does not regard this omission as a sin if the priest uses the formula of absolution with the intention of absolving from censure as well as sin, and he argues from the words of the Council of Trent, which says only that this clause is added laudabiliter. If, however, a penitent has incurred a censure and the priest first absolves from the sin and afterwards from the censure, such inversion of the order would be matter of grievous sin when the censure is excommunication debarring from the reception of the Sacraments; not, however, in the case of suspension or interdict.
This inversion would also be a grievous sin even if the priest intended to absolve from both sins and censures, although in this case the words absolvo te a peccatis tuis can be understood if the absolution from censures on account of the intimate connection between the two. Such an absolution, therefore, would be valid though given in defiance of the Church's prescription, for the censure does not affect the validity but only the lawfulness of the absolution.
The penitent must be present and the absolution pronounced over him by the confessor if it is to be valid. This is abundantly clear from the divine institution of the Sacrament, from the practice of the Church, and from a decree of the Head of the Church. Hence the absolution cannot be given in writing or by signs. According to the teaching of the Councils of Florence and Trent the form of this Sacrament, as of all the others (except that of matrimony, where a mere sign of consent is sufficient), is in the words which the priest must pronounce and articulate over the penitent. The Sacraments owe their institution to Christ; for, though matrimony existed as a divine institution before His coming, it was sanctified by Him and raised to the dignity of a means of grace in His Church. The essential rites of the Sacraments were defined by Christ, and we learn them from Scripture or tradition. We know from a uniform tradition that the form of all the Sacraments except matrimony consists essentially in words articulated by the lips; as for the Sacrament of Penance, the evidence is clear as well from the actual use prescribed in all penitentials and from the teaching of the Fathers, as from the decree of Eugenius IV to the Armenians.