These two psalms are almost certainly one poem split by a later chapter number. Psalm 43 has no title of its own, and the same refrain ends all three movements: 5"Why are you cast down, O my soul?" and the call to hope in God. One long song about thirst, in three acts.
The opening image is as physical as anything in the Psalter. 1"As a deer pants for flowing streams, so pants my soul for you, O God." The Hebrew word for soul can mean the throat, the very organ that thirsts. The line describes a whole creature longing for God the way a throat longs for water.
3"My tears have been my food day and night," while people ask, 3"Where is your God?" The taunt lands hard because it is also a question the psalmist asks himself. He remembers specifically what he has lost, going with the crowd in procession to the house of God with songs of praise. Now he writes from the north, from Hermon's heights, far from Zion.
Then he preaches to himself. This is deliberate self-address, and it does not suppress the feeling. He reminds his own soul of what it knows and has forgotten to feel.
The second movement changes the metaphor from drought to flood. 7"Deep calls to deep at the roar of your waterfalls," and all the breakers and waves go over him. The abundance of water that should comfort a thirsty man becomes the image of being overwhelmed. Yet in the same breath: 8"By day the LORD commands his steadfast love," and at night his song is with him. Suffering and covenant love sit side by side, and neither cancels the other. Tears by day, and a song through the night.
9"I say to God, my rock: 'Why have you forgotten me?'" The honesty is never edited for the sake of sounding more faithful. The taunt returns, and the refrain answers it a second time in the same words, though something in the repetition begins to feel like a truth being worn into the soul.
In the third movement, Psalm 43, he turns at last from talking to himself to talking to God. Two rounds of remembering and self-exhortation could not settle the ache, and prayer turned outward does what they could not: 3"Send out your light and your truth; let them lead me." The exile asks to be led home by God's light and truth walking ahead of him. At the altar he will find 4"God my exceeding joy." Joy is named as belonging to God himself.
The refrain closes the psalm a third time, and the whole poem has moved by the time it arrives. Jesus reached for this language in Gethsemane, "My soul is very sorrowful, even to death" (Matthew 26:38), using the Greek word the old translation uses for this psalm's "cast down." He admitted anguish and moved toward the Father, not away.
Whatever thirst has left your soul cast down, this psalm tells you where to aim the feeling.
Prayer
Father, our souls have panted as this deer pants, thirsty for you in seasons when tears were the only food we had. Thank you that you do not ask us to pretend the cast-down feeling away. Keep us preaching hope to our souls until we believe it. Send out your light and your truth to lead us home when we cannot find the way, and let your song play through even our darkest nights. In Jesus' name, amen.