John Calvin on John 4:26

26. It is I who talk with thee. When he acknowledges to the woman that; he is the Messiah, he unquestionably presents himself as her Teacher, in compliance with the expectation which she had formed; and, therefore, I think it probable, that he proceeded to give more full instruction, in order to satisfy her thirst. Such a proof of his grace he intended to give in the case of this poor woman, that he might testify to all that he never fails to discharge his office, when we desire to have him for our Teacher. There is, therefore, no danger that he will disappoint one of those whom he finds ready to become his disciples. But they who refuse to submit to him, as we see done by many haughty and irreligious men, or who hope to find elsewhere a wisdom more perfect — as the Mahometans and Papists do — deserve to be driven about by innumerable enchantments, and at length to be plunged in an abyss of errors. Again, by these words, “I who talk with thee am the Messiah, the Son of God,” he employs the name Messiah as a seal to ratify the doctrine of his Gospel; for we must remember that he was anointed by the Father, and that the Spirit of God rested on him, that he might bring to us the message of salvation, as Isaiah declares, (Isaiah 61:1.)

John 4:27-34

27. And, in the meantime, his disciples came, and wondered that he talked with the woman. But no man said, What seekest thou, or why talkest thou with her? 28. The woman, therefore, left her pitcher, and went away into the city, and said to the men, 29. Come, and see a man who hath told me all things that I ever did: is not this the Christ? 30. They went out of the city, therefore, and came to him. 31. In the meantime his disciples asked him, saying, Master, eat. 32. But he said to them, I have food to eat which you know not. 33. The disciples, therefore, said among themselves, Hath any man brought him any thing to eat? 34. Jesus saith to them, My food is, to do the will of him who sent me, and to finish his work.