All tears of godly sorrow drop from the eye of faith

(Thomas Brooks, "A Cabinet of Choice Jewels" 1669)

"They shall look upon Him whom they have pierced—and
 shall mourn." Zechariah 12:10

All godly sorrow is the fruit and effect of evangelical faith.
Godly sorrow flows from faith—as the stream from the fountain,
the branch from the root, and the effect from the cause. All
gracious mourning flows from looking, from believing. Nothing
breaks the heart of a sinner like a look of faith. All tears of
godly sorrow drop from the eye of faith. Godly sorrow
rises and falls—as faith rises and falls. The more a man is
able by faith to look upon a pierced Christ—the more his
heart will mourn over all the dishonors which he has done
to Christ. The more deep and wide the wounds are, which
faith shows me in the heart and sides of Christ—the more
my heart will be wounded for sinning against Christ.

The free love and favor of God, and His unspeakable goodness
and mercy manifested in Jesus Christ to poor sinners—is the
very spring and fountain of all evangelical sorrow. Nothing
breaks the heart of a poor sinner like the sight of God's free
love in Christ, the Redeemer. A man cannot seriously look upon
the firstness, the freeness, the greatness, the unchangeableness,
the everlastingness, and the matchlessness of God's free favor
and love in Christ—with a hard heart, or with dry eyes! It is
only such a love as this, which sets the soul a-mourning and
a-lamenting over a crucified Christ.

The fears of wrath, of hell, and of condemnation—works unsound
hearts to mourn. But it is the sight of a bleeding, dying Savior—
which sets sincere, gracious souls a-mourning.