In what sense is Jesus a "lamb?"

John 1:29 The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.

The common interpretation of this passage is to understand John to be describing Jesus as a sacrifice for sin, who, by vicariously suffering God's wrath, removes the sins of believers (or, in the case of Calvinists, of the "elect").

This is way off target.

First of all, the sin of the world was not removed when Jesus died.

Secondly, a "lamb" is not a significant animal in the sacrificial system. Adult goats, yes, though the animal that bears away the sin of the Jews on Yom Kippur is the scape goat - the goat that lives and carries the sins off into the wilderness.

Some suggest that a lamb is the figure of the Passover. Actually, the animal of the passover was also an adult flock animal, most likely a goat. But even if it were a lamb, it would not be a sacrifice for sin. Sin offerings were not eaten. Their bodies were burned outside of the camp:

Heb 13:11 For the bodies of those beasts, whose blood is brought into the sanctuary by the high priest for sin, are burned without the camp.

So in what sense IS Jesus a lamb?

The term "lamb of God" is similar to our expression, "God's kid," only without the flippancy. And it is not applied to any in Judaism but the Messiah. Furthermore, the figure is one of a violent purger of sin from the earth, not a sacrificial victim:

Testament of Joseph at
http://www.ccel.org/fathers2/ANF-08/anf08-15.htm
19. Hear ye also, my children, the visions which I saw. There were twelve deer feeding, and the nine were divided and scattered in the land, likewise also the three. And I saw that from Judah was born a virgin wearing a linen garment, and from her went forth a Lamb, without spot, and on His left hand there was as it were a lion; and all the beasts rushed against Him, and the lamb overcame them, and destroyed them, and trod them under foot. And because of Him the angels rejoiced, and men, and all the earth. And these things shall take place in their season, in the last days. Do ye therefore, my children, observe the commandments of the Lord, and honour Judah and Levi; for from them shall arise unto you the Lamb of God, by grace saving all the Gentiles and Israel. For His kingdom is an everlasting kingdom, which shall not be shaken; but my kingdom among yogi shall come to an end as a watcher's hammock, which after the summer will not appear.

So, taking away the sin of the world is an act of judgment. Think of Sylvester Stallone in "Lamb-O"!

Re 6:16 And said to the mountains and rocks, Fall on us, and hide us from the face of him that sitteth on the throne, and from the wrath of the Lamb:

Re 14:10 The same shall drink of the wine of the wrath of God, which is poured out without mixture into the cup of his indignation; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb:

Re 17:14 These shall make war with the Lamb, and the Lamb shall overcome them: for he is Lord of lords, and King of kings: and they that are with him are called, and chosen, and faithful.

Note that John expected this purging:

Mt 3:10 And now also the axe is laid unto the root of the trees: therefore every tree which bringeth not forth good fruit is hewn down, and cast into the fire.

Lu 3:9 And now also the axe is laid unto the root of the trees: every tree therefore which bringeth not forth good fruit is hewn down, and cast into the fire.

When Jesus didn't get with that program, John the baptizer doubted him:

Mt 11:3 And said unto him, Art thou he that should come, or do we look for another?

Lu 7:19 And John calling unto him two of his disciples sent them to Jesus, saying, Art thou he that should come? or look we for another?

Lu 7:20 When the men were come unto him, they said, John Baptist hath sent us unto thee, saying, Art thou he that should come? or look we for another?

So, perhaps the main figure in Christian iconography is based on a misinterpretation of the role of the lamb.