Ho! Everyone who thirsteth, come to the waters. And he that hath money, come, buy and eat. Is 55:1
Blessed are those who hunger and thirst for righteousness. Matt 5:6
Can anyone long for something in the midst of deep suffering? How can such a brain process anything other then alleviating pain?
Our Lord had one purpose and only one thing that He longed for and that was His Father, and to do His will.
At first reading what John writes is hard to understand, after this, knowing that all was now finished, Jesus said..."I thirst."
Our Lord had already done every task that He needed to do during His earthly ministry. He now could give attention to what He longed for. Though the sweetest earthly wine eventually turns to vinegar, the sweet wine of the Father satisfies and the moment of its sweetness lasts forever.