For a little over 200 years, Psalm 27 has been associated with the season of repentance: Some have the custom of reciting this psalm during Days of Awe (10 days), some for the whole month of Elul as well (40 days), and some beginning on Rosh Hodesh Elul and continuing through Hoshana Rabba (51 days). There are several explanations for this association. Most focus on the psalm’s themes; also noted: the expression “were it not” — לוּלֵא — in verse 13 spells Elul — אלול — backward.
Many siddurim include the full psalm somewhere in Psukei D’zimrah (verses of song, in the morning service). Mishkan T’filah includes the single verse, 27:4, for which there are a number of popular tunes (p.662 in “songs and hymns”).
some resources for exploring Psalm 30
So far the most thorough and useful commentary I’ve found on-line is still Schechter’s “A New Psalm”. [UPDATE 2017: Sadly, this on-line resource appears to be gone; Segal’s A New Psalm: The Psalms as Literature is now published by Geffen Books.] If anyone has a resource to suggest, please share.
A number of commentaries focus on the word “dilitani” — you have drawn me up — in the second verse: it reflects the Bible’s frequent use of wells/water imagery. But the language here connotes a pail pulled up from a well, which has to go down in order to rise in a useful way. And, as R. Benjamin Segal in the Schechter commentary notes, deep contrasts run throughout the psalm.
Joel Hoffman, in My People’s Prayer Book, notes that English has no direct way to translate the famous phrase:
בָּעֶרֶב יָלִין בֶּכִי וְלַבֹּקֶר רִנָּה
b’erev yalin bekhi v’laboker rinah
He suggests “tears abide” or “weeping spends the night” for “yalin bekhi.”