Zwingli:

1] Therefore the birth had to be absolutely pure of every stain, because He that was born was also God. Second, on account of the nature of the sacrificial victim. For that had to be free from all blemish, as the law of Moses required, though that only applied to the purity of the flesh, Heb 9:9. How much more had the victim to be absolutely spotless which made atonement for the sins not only of all who had been, but of all who were yet to come… Of this figure I shall say nothing more, since it is perfectly clear in itself and through the notices of all who have spoken of it. Furthermore, the John who baptized the Son of God, as soon as he saw Christ coming towards him, pointed out to his disciples with the words: “Behold the lamb of God that taketh away the sin of the world!” John 1:29. Zwingli, Commentary on True and False Religion, (Labyrinth Press), pp., 112 and 113.

2] A little while after he says [Jn 1:29-31]: “John seeth Jesus coming unto him, and saith, Behold the Lamb of God that taketh away the sin of the world… The divine Baptist shows by these words that Christ is the lamb that atones for the universal disease of sin, and that he himself is preaching a baptism of repentance before Him that He may be made manifest to Israel. For when man through repentance has come to the knowledge of himself, he is forced to take refuge in the mercy of God. But when he has begun to do that, justice makes him afraid. Then Christ appears, who has satisfied the divine justice for our trespasses. When once there is faith in Him, then salvation is found; for He is the infallible pledge of God’s mercy. For “he that gave up a Son for us, how will he not with him also give us all things?” Roms 8:32. Zwingli, Commentary on True and False Religion, (Durham, N.C: Labyrinth Press, 1981), 122-123.

3] Now as to those imposters who, not to keep silence when they cannot endure that all sins should be washed away through the grace of Christ (for they would rather, though they cannot make atonement, yet for pay received seen to do so)–who, I say, not to keep silence assert that Christ made atonement for original sin only, or for the sins of merely those who were before Him. Their error might be at once over-thrown by that single proclamation of the Baptist [John 1:29]: “Behold the Lamb of God, that taketh away the sin of the world”; for original sin is not the only sin in the world, and Christ takes away all the sins in the world. Yet I would by no means pass over the very clear testimony of 1 John 2:1-2, that they may not be able to plead any excuse. “Little children,” he says, “these things write I to you, that ye may not sin. And if any man sin, we have an advocate with the Father, Jesus Christ, the righteous: and he is the propitiation for our sins; and not for our only, but also for the sins of the whole world.”

With this testimony, then, I shall here be content, since it has been abundantly proved above that Christ is the means of salvation to all. Zwingli, Commentary on True and False Religion, (Durham, N.C: Labyrinth Press, 1981), pp., 155-156.

4] And again John the baptizer in Jn. 1:29, “Behold the lamb of God who takes away the sins of the entire world. Zwingli, Exposition and Basis of the Conclusions or Articles Published by Huldrych Zwingli, 29 January 1523, Pickwick Publications, vol 1, p, 16.

“Dost thou despise the riches? etc.” It does not seem to me, as some think, that there is here an argument, conclusive on two grounds, (dilemma,) but an anticipation of an objection: for as hypocrites are commonly transported with prosperity, as though they had merited the Lord’s kindness by their good deeds, and become thus more hardened in their contempt of God, the Apostle anticipates their arrogance, and proves, by an argument taken from a reason of an opposite kind, that there is no ground for them to think that God, on account of their outward prosperity, is propitious to them, since the design of his benevolence is far different, and that is, to convert sinners to himself. Where then the fear of God does not rule, confidence, on account of prosperity, is a contempt and a mockery of his great goodness. It hence follows, that a heavier punishment will be inflicted on those whom God has in this life favored; because, in addition to their other wickedness, they have rejected the fatherly invitation of God. And though all the gifts of God are so many evidences of his paternal goodness, yet as he often has a different object in view, the ungodly absurdly congratulate themselves on their prosperity, as though they were dear to him, while he kindly and bountifully supports them.

“Not knowing that the goodness of God, etc.” For the Lord by his kindness shows to us, that it is he to whom we ought turn, if we desire to secure our wellbeing, and at the same time he strengthens our confidence in expecting mercy. If we use not God’s bounty for this end, we abuse it. But yet it is not to be viewed always in the same light; for when the Lord deals favorably with his servants and gives them earthly blessings, he makes known to them by symbols of this kind his own benevolence, and trains them up at the same time to seek the sum and substance of all good things in himself alone: when he treats the transgressors of his law with the same indulgence, his object is to soften by his kindness their perverseness; he yet does not testify that he is already propitious to them, but, on the contrary, invites them to repentance. But if any one brings this objection that the Lord sings to the deaf as long as he does not touch inwardly their hearts; we must answer that no fault can be found in this case except with our own depravity. But I prefer rendering the word which Paul here uses, leads, rather than invites, for it is more significant; I do not, however, take it in the sense of driving, but of leading as it were by the hand.

“But according to thy hardness, etc.” When we become hardened against the admonitions of the Lord, impenitence follows; and they who are not anxious about repentance openly provoke the Lord. This is a remarkable passage: we may hence learn what I have already referred to that the ungodly not only accumulate for themselves daily a heavier weight of God’s judgments, as long as they live here, but that the gifts of God also, which they continually enjoy, shall increase their condemnation; for an account of them all will be required: and it will then be found, that it will be justly imputed to them as an extreme wickedness, that they had been made worse through God’s bounty, by which they ought surely to have been improved. Let us then take heed, lest by unlawful use of blessings we lay up for ourselves this cursed treasure. For the day, etc.; literally, in the day; but it is put for eis emeran ran, for the day. The ungodly gather now the indignation of God against themselves, the stream of which shall then be poured on their heads: they accumulate hidden destruction, which then shall be drawn out from the treasures of God. The day of the last judgment is called the day of wrath, when a reference is made to the ungodly; but it will be a day of redemption to the faithful. And thus all other visitations of God are ever described as dreadful and full of terror to the ungodly; and on the contrary, as pleasant and joyful to the godly. Hence whenever the Scripture mentions the approach of the Lord, it bids the godly to exult with joy; but when it turns to the reprobate, it proclaims nothing but dread and terror. “A day of wrath,” saith Zephaniah, “shall be that day, a day of tribulation and distress, a day of calamity and wretchedness, a day of darkness and of thick darkness, a day of mist and of whirlwind.” (Zephaniah 1:15.) You have a similar description in Joel 2:2, etc. And Amos exclaims, “Woe To You Who Desire The Day Of The Lord! What Will It Be To You? The Day Of The Lord Will Be Darkness, And Not Light.” (Amos 5:18.) Farther, by adding the word revelation, Paul intimates what this day of wrath is to be, that the Lord will then manifest his judgment: though he gives daily some indications of it, he yet suspends and holds back, till that day, the clear and full manifestation of it; for the books shall then be opened; the sheep shall then be separated the goats, and the wheat shall be cleansed from the tares. Calvin, Romans 2:4-5.