First use of the word “cup” in reference to the Cross is in Matthew 26:39.
“And He went a little beyond them, and fell on His face and prayed, saying, “My Father, if it is possible, let this cup pass from Me; yet not as I will, but as You will.”“ (Matthew 26:39, NASB)
The cup contained the sins of the world. Jesus Christ was sinless. 2 Cor. 5:21.
“He made Him who knew no sin to be sin on our behalf, so that we might become the righteousness of God in Him.” (2 Corinthians 5:21, NASB)
The Father judged those sins. Isaiah 53:4-6.
“Surely our griefs He Himself bore, And our sorrows He carried; Yet we ourselves esteemed Him stricken, Smitten of God, and afflicted. But He was pierced through for our transgressions, He was crushed for our iniquities; The chastening for our well-being fell upon Him, And by His scourging we are healed. All of us like sheep have gone astray, Each of us has turned to his own way; But the LORD has caused the iniquity of us all To fall on Him.” (Isaiah 53:4-6, NASB)
Christ drank from the cup. Drinking from the cup is a picture of the judgment of God’s wrath. John 18:11.
“So Jesus said to Peter, “Put the sword into the sheath; the cup which the Father has given Me, shall I not drink it?”“ (John 18:11, NASB)
The active voice and means that Jesus Christ deliberately drank from the cup. This was the free will of His humanity. The passive voice means that Jesus Christ received judgment for our sins. The Father’s wrath (absolute righteousness +R and Justice) fell upon the Son when He drank from the cup (when He bore the sins of the world).
God’s wrath is against sin, but was poured out on Christ. He drank the cup to the bottom (bore the sins of the whole world), therefore the Father’s wrath was poured out upon Him. The Father rejected human good for future judgment. Individuals choose human good or divine good. The work of Christ on the Cross was divine good.
If one rejects divine good (Christ’s work), they stand on their own merit (human good). Anyone standing on human good will have a cup from which he will drink, containing the wrath of God. Either accept Christ drinking for you on the Cross or accept the wrath of God on yourself. If you reject the Cross, then the alternative is the wrath of God. Either let Christ drink God’s wrath for you, or you drink it yourself.
In the Tribulation, Jesus Christ will be the judge and He will pour out the vials (drinking cups) of judgment on religious unbelievers. Rev. 16.
When He came at the First Advent, He drank the cup. When He comes again at the Second Advent, all unbelievers will drink the cup of wrath because they did not accept His drinking cup for them.