It's the Cup of God's Wrath
Isaiah 51:17+ NIV
The Cup of the LORD’s Wrath
17 Awake, awake! Rise up, Jerusalem, you who have drunk from the
hand of the LORD the cup of his wrath, you who have drained to
its dregs the goblet that makes people stagger.
21 Therefore hear this, you afflicted one, made drunk, but not
with wine. 22 This is what your Sovereign LORD says, your God,
who defends his people: “See, I have taken out of your hand the
cup that made you stagger; from that cup, the goblet of my wrath,
you will never drink again. 23 I will put it into the hands of your
tormentors, who said to you, ‘Fall prostrate that we may walk
on you.’ And you made your back like the ground, like a street to
be walked on.”
Again in Jeremiah.
Jeremiah 25+ NIV
The Cup of God’s Wrath
15 This is what the LORD, the God of Israel, said to me: “Take from
my hand this cup filled with the wine of my wrath and make all the
nations to whom I send you drink it. 16 When they drink it, they will
stagger and go mad because of the sword I will send among them.”
7 “Then tell them, ‘This is what the LORD Almighty, the God of Israel,
says: Drink, get drunk and vomit, and fall to rise no more because of
the sword I will send among you.’ 28 But if they refuse to take the
cup from your hand and drink, tell them, ‘This is what the LORD
Almighty says: You must drink it! 29 See, I am beginning to bring
disaster on the city that bears my Name, and will you indeed go
unpunished? You will not go unpunished, for I am calling down a sword
on all who live on the earth, declares the LORD Almighty.’
It goes on and on in Jeremiah. Of course, Revelation makes the last mention.
Revelation 14:10 (NIV)
10 they, too, will drink the wine of God’s fury, which has been poured
full strength into the cup of his wrath. They will be tormented with
burning sulfur in the presence of the holy angels and of the Lamb.
Revelation 16:19 (NIV)
19 The great city split into three parts, and the cities of the
nations collapsed. God remembered Babylon the Great and gave her the
cup filled with the wine of the fury of his wrath.
Your condemnation was to suffer God's wrath in hell for all of eternity. Jesus took your law place and was subjected to God's wrath on your behalf. There's nothing else in all of existence that God the Son would have so much stress over that He would sweat blood.