It is worth noting that when the early Christians thought about thirst—and especially the thirst of “the least of these my brethren” ––there was one thing they could readily connect these sayings to:
After this Jesus, knowing that all was now finished, said (to fulfill the scripture), “I thirst.” A bowl full of vinegar stood there; so they put a sponge full of the vinegar on hyssop and held it to his mouth. (John 19:28–29)
Jesus had thirsted. He had thirsted physically on the cross—an intense burning thirst brought on by massive loss of body fluids following his scourging. When he begged for drink, our wretched race gave him vinegar. And his followers got much the same treatment: crucified, stoned, cut to ribbons, roasted alive on spits. The torments we devised for the least of his brethren just goes on and on. In this light, the cup of cold water comes back into focus as a humble and sharp rebuke to human cruelty and selfishness. So small an act as this is impossible for the fallen human creature in the grip of Christ hatred. Indeed, it can, under the right conditions of mob mood, even mark you as “the wrong sort”: a sympathizer and fellow traveler who deserves the same fate as did Jesus. Just as Peter could imagine the hot breath of condemnation on his neck for the crime of having an accent similar to his (see Mark 14:70), so even the smallest act of perceived connection to Jesus can cost you your neck when the world is in the mood to persecute.
However, such is the divine generosity that even this small an act of charity to his saints can be what carries us into God’s light when the final reckoning comes. That is, I suspect, the meaning of this passage:
He who receives you receives me, and he who receives me receives him who sent me. He who receives a prophet because he is a prophet shall receive a prophet’s reward, and he who receives a righteous man because he is a righteous man shall receive a righteous man’s reward. And whoever gives to one of these little ones even a cup of cold water because he is a disciple, truly, I say to you, he shall not lose his reward. (Matthew 10:40–42)
To give drink to the thirsty in this context is to give drink to Christ himself, panting in desperation in the person of some helpless soul chased by a mob or harried into hiding by a pogrom. To be kind to a disciple fleeing persecution or to take in an apostle as a guest was, indeed, to give food and drink to Christ, as the Philippian jailer discovered when he welcomed Paul and Silas (see Acts 16:16–40).
But above all, to give drink to the thirsty would in the mind of the early Church most certainly have been connected with the gift of living water. Preaching the gospel in Rome or most of the urbanized areas subject to Caesar, in the shadow of the aqueducts, one would have been hard pressed to find bodies dying of thirst. But one could find a plentiful supply of souls hungering and thirsting after righteousness. To them the parable of the sheep and the goats would have been inevitably joined to the story of the Samaritan woman:
There came a woman of Samaria to draw water. Jesus said to her, “Give me a drink.” For his disciples had gone away into the city to buy food. The Samaritan woman said to him, “How is it that you, a Jew, ask a drink of me, a woman of Samaria?” For Jews have no dealings with Samaritans. Jesus answered her, “If you knew the gift of God, and who it is that is saying to you, ‘Give me a drink,’ you would have asked him, and he would have given you living water.” The woman said to him, “Sir, you have nothing to draw with, and the well is deep; where do you get that living water? Are you greater than our father Jacob, who gave us the well, and drank from it himself, and his sons, and his cattle?” Jesus said to her, “Every one who drinks of this water will thirst again, but whoever drinks of the water that I shall give him will never thirst; the water that I shall give him will become in him a spring of water welling up to eternal life.” (John 4:7–14)
To give drink to the thirsty is now, as it was then, a supreme work of mercy in that it involves giving the living water of the Spirit to those who cry out for him. To be sure, the bodily needs of the thirsty must be met. But because human beings are not brute beasts, they need more than this. They suffer from a thirst that no earthly water can satisfy. Indeed, as many an addict will tell you, it is a thirst that men have destroyed their lives seeking to quench with mortal elixirs promising life and delivering death. That is why the water at Jacob’s well—and indeed all the water in the world—could not slake the Samaritan woman’s thirst. Only Jesus can give us that water. And in the end it is only by this common yet miraculous drink that we can fully and truly give drink to the thirsty.
(For more information, see my book THE WORK OF MERCY: BEING THE HANDS AND HEART OF CHRIST (available here, signed by me, or in Kindle format here, or as an audiobook here).