Now here for further context from the old Roman Ritual is how converts to the Catholic Faith are instructed to be received.
RECEPTION OF CONVERTS AND PROFESSION OF FAITH
(As prescribed by the Sacred Congregation of the Holy Office on July 20, 1859; with the new form for abjuration of errors and profession of faith, approved by the Holy Office for the use of converts, and communicated through the Apostolic Delegate to the U. S. on March 28, 1942.)In the case of a convert from heresy, inquiry should first be made about the validity of his former baptism. If after careful investigation it is discovered that the party was never baptized or that the supposed baptism was invalid, he must now be baptized unconditionally. However, if the investigation leaves doubt about the validity of baptism, then it is to be repeated conditionally, using the ceremony for baptism of adults. Thirdly, if ascertained that the former baptism was valid, reception into the Church will consist only in abjuration of former errors and profession of faith. The reception of a convert will, consequently, take place in one of the following three ways:
I
If baptism is conferred unconditionally, neither abjuration of former errors nor absolution from censures will follow, since the sacrament of rebirth cleanses from all sin and fault.
II
If baptism is to be repeated conditionally, the order will be: (1) abjuration or profession of faith; (2) baptism with conditional form; (3) sacramental confession with conditional absolution.
III
If the former baptism has been judged valid, there will be only abjuration or profession of faith, followed by absolution from censures. But if the convert greatly desires that the full rites of baptism lacking hitherto be supplied on this occasion, the priest is certainly free to comply with his devout request. In this case he ought to use the form of baptism for adults, making those changes necessitated by the fact that baptism has already been validly conferred.
The priest vested in surplice and purple stole is seated in the middle of the altar predella, unless the Blessed Sacrament is reserved in the tabernacle--in which case he takes a place at the epistle side. The convert kneels before him, and with his right hand on the book of Gospels makes the profession of faith as given below. If the person is unable to read, the priest reads it for him slowly, so that he can understand and repeat the words after him.
Profession of Faith
I, N.N., .... years of age, born outside the Catholic Church, have held and believed errors contrary to her teaching. Now, enlightened by divine grace, I kneel before you, Reverend Father ...., having before my eyes and touching with my hand the holy Gospels. And with firm faith I believe and profess each and all the articles contained in the Apostles' Creed, that is: I believe in God, the Father almighty, Creator of heaven and earth; and in Jesus Christ, His only Son, our Lord, who was conceived by the Holy Spirit, born of the Virgin Mary, suffered under Pontius Pilate, was crucified, died, and was buried; He descended into hell, the third day He arose again from the dead; He ascended into heaven, and sits at the right hand of God, the Father almighty, from there He shall come to judge the living and the dead. I believe in the Holy Spirit; the holy Catholic Church; the communion of saints; the forgiveness of sins; the resurrection of the body, and life everlasting. Amen.
I firmly admit and embrace the apostolic and ecclesiastical traditions and all the other constitutions and ordinances of the Church.
I admit the Sacred Scriptures in the sense which has been held and is still held by holy Mother Church, whose duty it is to judge the true sense and interpretation of Sacred Scripture, and I shall never accept or interpret them in a sense contrary to the unanimous consent of the fathers.
I profess that the sacraments of the New Law are truly and precisely seven in number, instituted for the salvation of mankind, though all are not necessary for each individual: baptism, confirmation, holy Eucharist, penance, anointing of the sick, holy orders, and matrimony. I profess that all confer grace, and that baptism, confirmation, and holy orders cannot be repeated without sacrilege. I also accept and admit the ritual of the Catholic Church in the solemn administration of all the aforementioned sacraments.
I accept and hold in each and every part all that has been defined and declared by the Sacred Council of Trent concerning original sin and justification. I profess that in the Mass there is offered to God a true, real, and propitiatory sacrifice for the living and the dead; that in the holy sacrament of the Eucharist the body and blood together with the soul and divinity of our Lord Jesus Christ is really, truly, and substantially present, and that there takes place in the Mass what the Church calls transubstantiation, which is the change of all the substance of bread into the body of Christ and of all substance of wine into His blood. I confess also that in receiving under either of these species one receives Jesus Christ whole and entire.
I firmly hold that Purgatory exists and that the souls detained there can be helped by the prayers of the faithful.
Likewise I hold that the saints, who reign with Jesus Christ, should be venerated and invoked, that they offer prayers to God for us, and that their relics are to be venerated.
I firmly profess that the images of Jesus Christ and of the Mother of God, ever a Virgin, as well as of all the saints should be given due honor and veneration. I also affirm that Jesus Christ left to the Church the faculty to grant indulgences, and that their use is most salutary to the Christian people. I recognize the holy, Roman, Catholic, and apostolic Church as the mother and teacher of all the churches, and I promise and swear true obedience to the Roman Pontiff, successor of St. Peter, the prince of the apostles and vicar of Jesus Christ.
Moreover, without hesitation I accept and profess all that has been handed down, defined, and declared by the sacred canons and by the general councils, especially by the Sacred Council of Trent and by the Vatican General Council, and in special manner all that concerns the primacy and infallibility of the Roman Pontiff. At the same time I condemn and reprove all that the Church has condemned and reproved. This same Catholic faith, outside of which none can be saved, I now freely profess and I truly adhere to it. With the help of God, I promise and swear to maintain and profess this faith entirely, inviolately, and with firm constancy until the last breath of life. And I shall strive, as far as possible, that this same faith shall be held, taught, and publicly professed by all who depend on me and over whom I shall have charge.
So help me God and these holy Gospels.
The convert remains kneeling, and the priest, still seated, says psalm 50, or psalm 129, concluding with "Glory be to the Father."
After this the priest stands and says:
Lord, have mercy. Christ, have mercy. Lord, have mercy. Our Father (the rest inaudibly until:)
P: And lead us not into temptation. All: But deliver us from evil. P: Save your servant. All: Who trusts in you, my God.
P: Lord, heed my prayer. All: And let my cry be heard by you. P: The Lord be with you. All: May He also be with you.
Let us pray. God, whose nature is ever merciful and forgiving, accept our prayer that this servant of yours, bound by the fetters of sin, may be pardoned by your loving kindness: through Christ our Lord. All: Amen.
The priest again sits down, and facing the convert pronounces the absolution from excommunication, inserting the word perhaps if in doubt as to whether it has been incurred:
By the authority of the Holy See which I exercise here, I release you from the bond of excommunication which you have (perhaps) incurred; and I restore you to communion and union with the faithful, as well as to the holy sacraments of the Church; in the name of the Father, and of the Son, + and of the Holy Spirit. Amen.
Lastly the priest imposes some salutary penance, such as prayers, visits to a church, or the equivalent.