What if I don't feel God at all? Is this psalm only for people who do?
Look at what this writer has: a thirst, an empty place where something used to be, and a voice that says all day, "Where is your God?" (verses 4 and 11). The psalm does not start from closeness.
The old commentators spell out what the taunt means. Radak hears it as: if He is the true God and you serve Him, He would have saved you and brought you out of exile. Ibn Ezra (a Spanish commentator of the 1100s) gives another reading: you used to go up three times a year to see Him, and now you cannot.
So the thirst is for something the writer once had: the walk up with the crowd, the singing, the House of God (verse 5). Rashi and Radak both say this is the memory.
Now notice what the writer does with the gap. He does not hide it. In verse 10 he calls God "my rock" and in the same sentence asks, "Why have You forgotten me?"
The psalm itself does three things: it remembers (verse 5), it talks to its own soul (verse 6), and it waits. Rashi reads the word for "hope" in verse 6 as: wait, and look forward to the redemption.
Tehillim 42:4, 42:5, 42:11; Radak on Tehillim 42:4,Ibn Ezra on Tehillim 42:4; Rashi on Tehillim 42:5 and 42:6Why does the writer argue with his own soul instead of just praying?
Verses 6 and 12 are almost the same sentence: "Why are you bowed down, my soul, and why do you moan within me? Hope in God, for I will yet thank Him." The writer talks to his soul as if it were another person.
Radak explains the order. First the soul pours itself out as the writer remembers the festivals. Then he turns back and comforts it: why are you bowed down, my soul? Hope in God.
Metzudat David is more blunt about what happens next. Right after the comfort, he says, it is as if the soul turns again to complain. That is verse 7: my soul is bowed down within me, because I remember the good I had from You. At verse 12 he says the writer turns again to comfort it.
So this is not a straight line from sad to calm. It goes sad, comforted, sad again, comforted again.
What does the comfort actually say? It does not say the trouble is over. The words are od odenu, "I will yet thank Him." Radak explains that the writer will still thank God for the rescue that is coming. The thanks is in the future. Rashi adds that the word for "hope" means to wait.
Radak on Tehillim 42:6 and 42:12,Metzudat David on Tehillim 42:6, 42:7 and 42:12,Rashi on Tehillim 42:6Does this psalm say my troubles are my fault?
In verse 8 the writer says to God, "All Your breakers and Your waves have passed over me." In verse 10 he asks, "Why have You forgotten me?" So whose fault is the flood? The sources do not agree.
Radak (Rabbi David Kimchi, Provence, around 1200) says the writer calls them "Your" waves because God brought them on us for our sins.
Midrash Tehillim (a collection of rabbinic teachings on Tehillim) lets the psalm push back. The people in Egypt kept one commandment and were redeemed, it has Israel say. I keep all of them, so why have You forgotten me? Rashi quotes this reading.
The same Midrash gives God's side as well. Israel says the right hand above has changed. God answers with Yeshayahu (Isaiah) 59: Hashem's hand is not too short to save, but your sins have been a barrier between you and your God.
Ibn Ezra gives a reason that blames no one. The writer asks "why" because of how long the exile has lasted.
Two cautions. First, all of these sources are talking about the exile of the whole Jewish people, in a psalm written as "I" so that each person can say it. They do not rule on one person's hard week. The Gemara takes up personal troubles in another place. Rava (some say Rav Chisda) says that someone who sees troubles coming should look into his own deeds. If he finds nothing, he should think about time lost from Torah study. If that is not it either, they are "sufferings of love" (Berakhot 5a). Second, the psalm itself does not settle the question. The question is asked, and the writer keeps waiting.
Tehillim 42:8 and 42:10; Radak on Tehillim 42:8,Midrash Tehillim 42:4 and 42:5; Yeshayahu 59:1-2,Rashi and Ibn Ezra on Tehillim 42:9 and 42:10,Berakhot 5a