Psalm 72:6-7: May he come down like rain upon the mown grass, like showers that water the earth. In his days may the righteous flourish, and abundance of peace till the moon is no more.
The Spirit is like water from heaven. Judah is a wasteland “until the Spirit is poured out upon us from on high (Isaiah 32:15). Yahweh promises to “pour out streams on the thirsty land,” and in the next breath says “I will pour out my Spirit on your offspring” (Isaiah 44:3).
The Son too is water from heaven. The king is like “rain upon the mown grass,” the Psalmist tells us, “like showers that water the earth.” Jesus is the Bread of Life, rained from heaven like manna in the wilderness. He is the rain that the Father sends upon the just and unjust.
At Christmas, we celebrate the beginning of the Father’s work of turning the wasteland into a watered garden. Through the rain of the Son and the flood of the Spirit, our Father makes withered land flourish with righteousness and peace. When His rain falls, it produces vegetation useful for those for whose sake it was tilled.
That rain falls at every baptism. your son is made of earth, and the water comes down on him with the promise of the Son and Spirit. This water falls to make him as fruitful as new creation.
Land must be tilled. You’ll have to pull weeds. You’ll have to prune. You’ll have to water him again and again by reminding him of this baptismal water, by telling him to trust in the Son and Spirit who water him here on this day. The gardening starts here, when Jesus and His Spirit fall like rain on mown grass, like showers to water the earth.