John Calvin Commentary John 4:28

"So the woman left her waterpot, and went away into the city, and saith to the people," — John 4:28 (ASV)

Therefore the woman left her pitcher. This circumstance is related by the Evangelist to express the fervor of her zeal, for it is an indication of haste that she leaves her pitcher and returns to the city. And this is the nature of faith: when we have become sharers in eternal life, we wish to bring others to share it with us. Nor is it possible for the knowledge of God to lie buried and inactive in our hearts without being revealed to others, for that saying must be true:

I believed, and therefore I will speak (Psalms 116:10).

The woman's sincerity and promptness are all the more worthy of attention because it was only a small spark of faith that kindled them, for scarcely had she tasted Christ when she spread His name throughout the whole city. For those who have already made moderate progress in His school, inactivity will be highly disgraceful.

But she may appear to deserve blame on this account: that while she is still ignorant and imperfectly taught, she goes beyond the limits of her faith. I reply, she would have acted thoughtlessly if she had assumed the role of a teacher; but when she desires nothing more than to encourage her fellow citizens to hear Christ speak, we will not say that she forgot her place or went further than she had a right to do. She merely serves as a trumpet or a bell to invite others to come to Christ.