“fountain of tears that I might weep.” Jeremiah is known as the “weeping prophet” because of verses such as this (cp. Jer. 9:10; 14:17) and because of his writing the book of Lamentations. The Hebrew translated “fountain” means “spring,” a place where water bubbles up out of the ground, an apt description for crying, where tears well up from the eyes. Of all the prophets and men and women of God in the Bible, Jeremiah most openly shows his love for the people in the fact that in spite of their egregious sin and what they do to Jeremiah, he weeps and cries over them. In many verses, Jeremiah openly reveals the deep emotional hurt he has because of the sin of his people and the consequences of that sin (cp. Jer. 8:21, 9:1; 10:19-20; 13:17; 14:17).
“the daughter of my people.” An idiom of endearment meaning my dear people (see commentary on Jer. 8:21).