Ulrich Zwingli, in the first period of his reformatory labors, frankly questioned the practice of infant baptism. He wrote in July, 1523, in his Exposition of the Articles (article eighteen):
The rite of Confirmation became customary only after a general beginning had been made to baptize the children in their infancy, or immediately after birth. Confirmation was introduced that the faith which was confessed for them by their fathers and mothers through their godfathers might not be unknown to them [since they were instructed previous to confirmation]. Although I know, as the ancients indicate, that from the earliest times infants were sometimes baptized, it was nevertheless not so common a custom as it is in our time, but the general practice was, as soon as they arrived at the age of reason, to form them into classes for instruction in the word of salvation (hence they were called catechumens, i.e. persons under instruction) and when they steadfastly believed in their hearts and confessed with their mouths, they were baptized.
Balthasar Hubmaier, one of the spokesmen of the Anabaptists, wrote in his reply to Zwingli’s Book ‘On Baptism’:
In the year 1523, about the day of Philip and James [May 1], I have conferred with you [Zwingli] on the moat of Zurich upon the Scriptures which treat on baptism. Then and there you agreed with me in the opinion that children should not be baptized before they were instructed in the faith; you said, this was the custom in times of yore, therefore such were called catechumens. You promised to mention this in your forthcoming book, as you also did in article XVIII on Confirmation. Anyone can read it and find your opinion clearly expressed. Sebastian Ruckensberger of St. Gall, at that time prior of the cloister Sion at Klingnau, was present.
To his friend Thomas Wyttenbach Zwingli wrote on June 15, 1523: “It is useless to wash a thousand times in the baptismal water him who does not believe.”In a letter to Fridolin Lindauer in Bremgarten he said, October 20, 1524: “God has commanded to baptize those who have previously believed.” “More and more Zwingli looked upon baptism as an act for believers,” says the Zwinglian theologian Usteri, “namely an act of confession and of acceptance of definite duty.”
It is worthy of notice that Zwingli, even after he had decided that infant baptism must not be abandoned, did not hold that this practice is commanded in Scripture. He says in December, 1524: “To come to the subject of infant baptism, observe that those who would not baptize them have no clear scriptural commandment that infants should not be baptized, and again, those who baptize them have no clear Scripture which commands that they should be baptized. — So we find in the New Testament neither a command nor a prohibition of infant baptism.” Zwingli’s defence of the practice of the state-church was based on the supposition that the baptism of infants is not forbidden in Scripture.
We have Zwingli’s own testimony to the effect that for some time he openly favored the abolition of infant baptism. He says in 1525: “When we readily accepted the opinion that the signs [ordinances] strengthen the faith, we naturally contradicted infant baptism; for baptism can not strengthen the faith in the instance of infants, for they can not believe. For the error misled me also some years ago that I thought it would be much better to baptize children after they have arrived at a good age.” Hubmaier, commenting on this statement of Zwingli, says: “Yes, this was your opinion; you have set forth this view in writing and have preached it from the pulpit; many hundreds of people have heard it out of your own mouth.”
Conrad Grebel, the foremost leader of the Swiss Anabaptists, wrote in December, 1524, to the Council of Zurich: “I am convinced that Zwingli is of the same opinion concerning baptism as we, and I do not understand for what reason he does not confess it. But this I know with certainty, if only God’s Word is permitted to prevail, no one may disprove this opinion.” “I do not know, what to make of it,” says Hans Hottinger concerning Zwingli, “today he preaches one thing and tomorrow he recants it. And particularly he has preached years ago that the infants should not be baptized, but now he says, they should be baptized.” A Zwinglian chronicler of Zurich also testifies that Zwingli preached against infant baptism.
“It is an altogether true and therefore very sincere confession,” says August Baur, the author of the most notable work on the Zwinglian theology, “which Zwingli makes in his Book on Baptism, when he says, the error misled him some years ago that he believed, it were far better to abandon infant baptism,” and Usteri says: “Zwingli does not leave us in the dark concerning the position which he first took on the question of infant baptism.” W. Hadorn also testifies that Zwingli, and other reformers had at first similar opinions about infant baptism as those who later became the leaders of the Anabaptists. Another Zwinglian historian says: “The abolition of the baptism of new-born children was without any doubt an altogether consequential point in the program of the earlier theology of Zwingli.” This is clear testimony to corroborate the statement of the Moravian Anabaptist chronicler who informs us that Ulrich Zwingli, together with Conrad Grebel recognized infant baptism as uncalled for, but somewhat later, when Grebel and Mantz urged the necessity of faith-baptism, Zwingli would not consent to it.