Charles H. Spurgeon on Psalms 126:5

They that sow in tears shall reap in joy. Gospel tears are not lost; they are seeds of comfort: while the penitent doth pour out tears, God pours in joy. If thou wouldst be cheerful, saith Chrysostom, be sad. It was the end of Christ's anointing and coming into the world, that he might comfort them that mourn: Isa 61:3. Christ had the oil of gladness poured on him, as Chrysostom saith, that he might pour it on the mourner; well then might the apostle call it "a repentance not to be repented of": 2Co 7:10 ...Here is sweet fruit from a bitter stock: Christ caused the earthen vessels to be filled with water, and then turned the water into wine: Joh 2:9. So when the eye, that earthen vessel, hath been filled with water brim full, then Christ will turn the water of tears into the wine of joy. Holy mourning, saith St. Basil, is the seed out of which the flower of eternal joy doth grow. —Thomas Watson (-1690?), in "The Beatitudes."