Zwingli:

1) 6: For Jesus Christ is the leader and captain whom God has promised and given to the whole human race. Zwingli’s Sixty-seven Articles of 1523. [Source: Reformed confessions of the 16th century, ed., by Cochrane, Arthur C., ed. (Philadelphia, Westminster Press 1966), 36.]

2) “That Christ was offered himself up once as a sacrifice, is a perpetual and valid payment for the sin of all believers…

For just as all persons die only once, and immediately after their death follows the judgement of God, so Christ has offered himself only once through the death he suffered. And after his death follows the taking away of the sin of all, i.e., of all who believe…

But if he were to be offered up again and again, he would be much like the sacrifices in the Old Testament which had to be offered up repeatedly because of their imperfection. This would mean a belittling and degrading of the perfection of the sacrifice which is Christ who through his death has offered himself to God for the sins of all who ever been and ever shall be. Zwingli, Exposition and Basis of the Conclusions or Articles Published by Huldrych Zwingli, 29 January 1523, Pickwick Publications, 1:92, 93, and 94.

3) Article 3 Christ is the only wisdom, righteousness, redemption, and satisfaction for the sins of the whole world. The Berne Theses [published and revised later by Zwingli, written by Berthold Haller and Francis Kolb.] [Source: Translated in Schaff Creeds of Christendom, 1:365.]

General Interest:

1) 5: The Purpose of Holy Scripture and That to Which it Finally Points. The entire Biblical Scripture is solely concerned that man understand that God is kind and gracious to him and that He has publically exhibited and demonstrated His kindness to the whole human race through Christ His Son. However, it comes to us and is received by faith alone, and is manifested and demonstrated by love for his neighbor. The First Helvetic Confession. [Source: Reformed confessions of the 16th century, ed., by Cochrane, Arthur C., ed. (Philadelphia, Westminster Press 1966), p., 101.]¹

See also the Zwingli File

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¹In case it is doubted, that by the phrase “whole human race” Zwingli meant the whole human race, see his comment 8: Concerning Original Sin. Thus original and inherited sin has so permeated the whole human race and has so ruined and poisoned it that man, who had come a child of wrath and an enemy of God, could not be saved or restored by anyone except God through Christ. The First Helvetic Confession. [Source: Reformed confessions of the 16th century, ed., by Cochrane, Arthur C., ed. (Philadelphia, Westminster Press 1966), 102.]