The prohibition of the marriage of priest is a man-made law by the Roman Catholic Church. This is what the Augsburg Confession has to say:
XXIII. The Marriage of Priests
1 There has been common complaint concerning priests who have not been continent. 2 On this account Pope Pius is reported to have said that there were some reasons why priests were forbidden to marry but that there are now far weightier reasons why this right should be restored. Platina writes to this effect.3 3 Since priests among us desired to avoid such open scandals, they took wives and taught that it was lawful for them to contract matrimony. 4 In the first place, this was done because Paul says, “Because of the temptation to immorality each man should have his own wife” 7
10 It is also evident that in the ancient church priests were married men. 11 Paul said (tr-63) that a married man should be chosen to be bishop (1 Tim. 3:2), 12 and not until four hundred years ago were priests in Germany compelled by force to live in celibacy.4 In fact, they offered such resistance that the archbishop of Mayence,5 when about to publish the Roman pontiff’s edict on this matter, was almost killed by the enraged priests in an uprising. 13 In such a harsh manner was the edict carried out that not only were future marriages prohibited but existing marriages were also dissolved, although this was contrary to all laws, divine and human, and contrary even to the canons, both those made by the popes and those made by the most celebrated councils.6
14 Inasmuch as the world is growing old and man’s nature is becoming weaker, it is also well to take precautions against the introduction into Germany of more vices.
15 Besides, God instituted marriage to be a remedy against human infirmity. 16 The canons themselves state that in later times the old rigor should be relaxed now and then on account of man’s weakness, and it is devoutly to be desired that this be done in the case of sacerdotal marriage. 17 And it seems that the churches will soon be lacking in pastors if marriage continues to be forbidden.
18 Although the commandment of God is in force, although the custom of the church is well known, and although impure celibacy causes many scandals, adulteries, and other crimes which deserve the punishments of just magistrates, yet it is a marvelous thing that nowhere is greater cruelty exercised than in opposition to the marriage of priests. 19 God has commanded that marriage be held in honor. 20 The laws of all well-ordered states, even among the heathen, have adorned marriage with the greatest praise. 21 But now men, and even priests, are cruelly put to death, contrary to the intent of the canons, for no other cause than marriage. 22 To prohibit marriage is called a doctrine of demons by Paul in 1 Tim. 4:3. 23 This can be readily understood now that the prohibition of marriage is maintained by means of such penalties.
(tr-65) 24 Just as no human law can nullify a command of God, so no vow can do so. 25 Accordingly Cyprian advised that women who did not keep the chastity which they had promised should marry. His words in the first book of his letters, Epistle XI, are these: “If they are unwilling or unable to persevere, it is better for them to marry than to fall into the fire through their lusts; at least they should give no offense to their brothers and sisters.”
26 The canons show some consideration toward those who have made vows before attaining a proper age, and as a rule vows used to be so made in former times.