Zwingli's views on baptism were largely a response to Anabaptism, a movement which attacked the practice of infant baptism. He defended the baptism of children by describing it as a sign of a Christian's covenant with disciples and God just as God made a covenant with Abraham.
He developed the symbolic view of the Eucharist. He denied the Catholic doctrine of transubstantiation and following Cornelius Henrici Hoen, he agreed that the bread and wine of the institution signify and do not literally become the body and blood of Jesus Christ. Zwingli's differences of opinion on this with Martin Luther resulted in the failure of the Marburg Colloquy to bring unity between the two Protestant leaders.
Zwingli believed that the state governed with divine sanction. He believed that both the church and the state are placed under the sovereign rule of God. Christians were obliged to obey the government, but civil disobedience was allowed if the authorities acted against the will of God. He described a preference for an aristocracy over monarchic or democratic rule.
The Bible is central in Zwingli's work as a reformer and is crucial in the development of his theology. Zwingli appealed to scripture constantly in his writings. This is strongly evident in his early writings such as Archeteles (1522) and llarity and Certainty of the Word of God (1522). He believed that man is a liar and only God is the truth. For him scripture, as God's word, brings light when there is only darkness of error.
Zwingli initially appealed to scripture against Catholic opponents in order to counter their appeal to the church—which included the councils, the church fathers, the schoolmen, and the popes. To him, these authorities were based on man and liable to error. He noted that "the fathers must yield to the word of God and not the word of God to the fathers". His insistence of using the word of God did not preclude him from using the councils or the church fathers in his arguments. He gave them no independent authority, but he used them to show that the views he held were not simply his own.