"Drinking of the cup" in the Scriptures has several meanings.
Let's examine some of them.
When a young Hebrew man and woman were about to be betrothed, the groom would pour wine into a cup and then offer it to the woman. She had a choice to make at this point. If she accepted and drank of the cup, she was considered as being betrothed to him. It was said that she drank of the marriage covenant or contract. If she refused, the marriage was off.
Throughout the Scriptures, we see the Lord Jesus offering the "cup" to His people - inviting them to be betrothed to Him and to drink of the marriage covenant or contract. He is also inviting them to be forgiven of their sins so that they can become just like Him - sinless, spotless, and without fault - in the Marriage Supper.
Matthew 26:28 says - "For this is My blood of the new testament, which is shed for many for the remission of sins."
Mark 14:24 says - "And He said unto them, This is My blood of the new testament, which is shed for many."
1 Corinthians 11:25 says - "After the same manner also He took the cup, when He had supped, saying, This cup is the new testament in My blood: this do ye, as oft as ye drink it, in remembrance of Me."
The wine in the cup represented Jesus' blood to be shed. It also represented the new covenant that God was about to make through Him as the Mighty Redeemer. The blood shed confirmed the covenant and purchased the remission of sins - making the "woman" acceptable in the sight of God - a worthy bride for His Son.
In 2 Corinthians 11:2, we see the Apostle Paul as the agent in joining many in wedlock to Christ - "For I am jealous over you with godly jealousy: for I have espoused you to one husband, that I may present you as a chaste virgin to Christ." Here we see how through the preaching of the Gospel (the preaching of the Blood and the Cross), the "woman" or people are offered the cup for the ratification of the marriage covenant and also for the remission of their sins. If they accept this "cup," they become a part of Christ's bride - "a chaste virgin" to Him. That is the only kind of bride He will accept.
Besides representing the marriage covenant, "drinking the cup" had several other meanings as well. For one, it meant to accept whatever the cup represented. We see this aptly displayed in the conversation Jesus had with the mother of James and John in Matthew 20:22-23 - "But Jesus answered and said, Ye know not what ye ask. Are you able to drink of the cup that I shall drink of, and to be baptized with the baptism that I am baptized with? They say unto Him, We are able. And He saith unto them, Ye shall drink indeed of My cup, and be baptized with the baptism that I am baptized with..."
What exactly was in Jesus' "cup" that James and John would have to drink from? Part of His "cup" entailed suffering. To drink from His "cup" meant that James and John would have to suffer with Him and experience whatever He ordained for them. It meant that they were symbolically pledging that they were willing to walk down the same path that He walked with similar consequences. And indeed they did! James turned out to be the first apostle to be martyred. John suffered greatly in the hands of persecutors - spending many years in exile on the isle of Patmos and even miraculously surviving being boiled in oil!
"Are ye able to drink of the cup that I shall drink of...We are able...Ye shall drink indeed of My cup..."
Besides pledging to be the Bride of Christ, when you drink from His "cup," you are proclaiming your willingness to share in similar trials as He did. You are willing to endure whatever He has appointed for you as your lot. "...O My Father, if it be possible, let this cup pass from Me: nevertheless, not as I will, but as Thou wilt...O My Father, if this cup may not pass away from Me, except I drink it, Thy will be done." (Matthew 26:39 and 42)
"Drinking from His cup" also meant that you were identifying yourself exclusively with Him. In Psalm 16:5, David said - "The LORD is the portion of mine inheritance and of my cup..." What He was saying was that the Eternal God was his "cup." In other words, He was his only source of refreshment, comfort, and happiness. It was the Lord Who cheered, refreshed, and sustained him in life - none other!
David was also proclaiming that he would not serve two masters - that he could not simultaneously identify with Christ and Satan. His life, actions, words, and thoughts continuously announced Who was his Father - God in heaven and not the devil. Making the LORD his "cup" or "drinking from His cup" meant that he made the quality decision to live God's way of life and renounce the way of the evil one.
At the final Passover, after taking the cup and giving thanks, Jesus said to His disciples in Matthew 26:27-28 - "...Drink ye all of it; For this is My blood of the new testament, which is shed for many for the remission of sins." When they took a sip from His cup - from the cup of Christ as the Lamb of God - they were literally announcing that Jesus alone was their "cup." They were renouncing the "cup" of this world or Babylon - who "glorifies herself" and "lives deliciously" (Revelation 18:7) - showing forth the impossibility for a believer to "drink of the Lord's cup" and the "cup of demons" at the same time. They were totally rejecting this world - Babylon - and the awful "cup" of the false church which is full of Babylon's abominations and the blood of the saints.
"Drink ye all of it."
In this verse, Jesus is beckoning to His people to come and "drink of His cup" - while - in doing so - making Him #1 and renouncing the world's system of evil.
He is also calling to them to "drink of His cup" entirely. A full commitment is required - not a partial one. Total surrender is the only one that is acceptable. There cannot be this type of "Christianity" which we see among so many today of having one foot in the world and one foot in Jesus. "Drink ye all of it." In other words, drink all of its contents. No sipping is allowed. "Having a form of godliness, but denying the power thereof" (2 Timothy 3:5) is not acceptable. It is going all the way with Jesus or nothing at all!
In John 18:11, the Lord Jesus inquired - "...the cup which My Father hath given Me, shall I not drink it?" Today, the Lord Jesus Is asking you - "..the cup which I now give you, will you not drink it?" This "cup" entails betrothal to Him alone - not having any other lovers or rivals. It includes total separation from the world, the flesh, and the devil. It means that you are pledging your life, actions, words, and thoughts for His honor and glory - proving that He is your Father and not Satan. It also involves suffering - being willing to walk down the same path that He walked with similar consequences.
It also involves being His "cupbearer." In Old Testament times, monarchs feared being poisoned by those around them so they hired a "cupbearer" to sample the drink first. If it was poisoned, the cupbearer died, and the king's life was spared. In this situation, "drinking the cup" symbolized sharing the consequences of what was in the cup... accepting what the king dealt out...or accepting whatever is appointed for one to experience.
Being a "cupbearer" was an awesome privilege, but it certainly came with its consequences. The "cupbearer" was frequently in the presence of the king - participating in whatever the king did. However, this position also required that he would participate in whatever the cup contained - sometimes suffering or even death.
It was so important that before Passover the recipient of the "cup" examined himself (1 Corinthians 11:25-31). To "drink this cup of the Lord, unworthily" carried serious results - chastisement or judgment of some sort. It was vital to always have a proper attitude toward God before partaking of this "cup."
For all those who endured to the very end...stayed on course...or tread the same narrow path as Jesus did, this "cup" brought glorification - "If we suffer, we shall also reign with Him: If we deny Him, He also will deny us" (2 Timothy 2:12). For those who shared in His shame and suffering, they were guaranteed a share in His glory. If they overcame in this life, they certainly savored the victory by Him. If they died with and for Him, they were also resurrected in His likeness. This time the "cup of the Lord" became a "cup of salvation" (2 Corinthians 2:14).
"Are ye able to drink of the cup that I shall drink of...?"
Watch how you answer this question! If you say that you are able, then get ready to "drink indeed of Jesus' cup" which inevitably includes suffering.
However, know this - if you do "drink of His cup" in submission, then glorification will surely follow.
"Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink His blood, ye have no life in you. Whoso eateth my flesh, and drinketh My blood, hath eternal life...For My flesh is meat indeed, and My blood is drink indeed. He that eatheth My flesh, and drinketh My blood, dwelleth in Me, and I in Him" (John 6:53-56).