Zwingli's understanding of baptism and communion as an "oath"

Ulrich Zwingli (d. 1531), like his contemporary Martin Luther (d. 1546), was a courageous reformer of the church, to whom Protestant Christians owe a debt of gratitude. He began his reform at Zurich in 1519 by preaching through the gospel of Matthew, reviving the practice of Chrysostom of consecutive Bible exposition. Zwingli simplified the worship of the church, purging it of unbiblical elements, and limiting it to what God had expressly commanded. In his theology, Zwingli exalted God's sovereign will in providence and salvation, and affirmed the chasmic difference between Creator and created. Zurich became a hub from where the Reformation spread out to other cities such as Berne, Strasburg and Geneva.  

On one point, however, Zwingli was deficient, namely in respect of baptism and the Lord's Supper.  

Zwingli's paradigm for understanding the sacraments was the Latin word sacramentum, equivalent to the German word "Eid". This referred to a soldier's oath of obedience. Zwingli understood the sacraments in terms of an expression of our allegiance to God: in baptism and the Supper we swear allegiance to God to obey him. "Baptism is an initiatory sign or badge initiating us to a lifelong mortification of the flesh and engaging us like a soldier at their enlistment." This is a different perspective from one whereby the sacraments are about God's action, means of grace which confirm God's promise of salvation to us in outward and tangible form. 

Moreover, Zwingli defended the practice of infant baptism vis-a-vis the Swiss Brethren ("Anabaptists"). In so doing, Zwingli drew on the parallel between New Testament circumcision and Old Testament baptism. In Zwingli's view, this sign of the covenant (circumcision under the Old Covenant, baptism under the New) was not only for believers, but also for their children, who are "holy" by virtue of a Christian parent (1 Cor 7:14). 

While, in Zwingli's view, baptism neither conferred the status of being "holy" (in his view Christian infants are born with this status), nor did delivered salvation, it *did* obligate infants to be Christians. Infant baptism, i.e. baptism when the person baptised is unable to make their own response, was understood to be the dedication of the child to God by the parent. 

To fail to baptise infants, or to make the baptism contingent upon the willingness of an adult to "opt in" to Christian faith and commitment, as was the case with the Swiss Brethren, appeared seditious, amounting to individuals and communities "opting out" of Christian society and rejecting their obligations, rather like citizens refusing enlistment "en masse". Incidentally, Anabaptists refused to take up arms in a society where military service to defend the Swiss cantons was a necessity.