Ps 30.5-6 5 Sing to Yahweh, O faithful ones of His!
And praise the memories of His devotion!
6 For a moment is in his anger,
but a lifetime in his favor.
In the evening Weeping may spend the night,
But a shout of joy comes in the morning.
 The audience has shifted from God to God's people. This marks the beginning of the next strophe.
 The word translated devotion is an often misunderstood term. Consider the following NET translation and NET note:
Give thanks to His holy name.
“The LORD’s “name” is “holy” in the sense that it is a reminder of his uniqueness and greatness.”
But thanks to some recent work by Peter Gentry, a more accurate description of what this loaded word communicates is becoming more apparent. In short, it might be said that the Hebrew word קדשׁ—often translated as holy/holiness—does not describe (or at least primarily so) a moral status or ethical state of perfection but rather the devotion of a person or thing to a specific end or purpose. For this verse, that would mean…
The hasîd (faithful) are told to "praise", "confess", or more simply, to "talk about" their memories of his devotion (קדשׁ)—not moral, absolute purity (which is a product of his קדשׁ, but not the thing itself). If one reflects on how God has acted in the past, as the poet does in vss. 2-4, then one does not remember God's moral hygiene, but his acts of deliverance—of his devotion in saving those who call to him.
The fact that we are told to reflect on God's devotion and not the quality of his purity his further evidenced in how the poet addresses those who are to do this reflecting: they are the hasîd, the doers and objects of his hesed—his beneficent devotion.
 A possible reading of this verse is the following: For in his anger is death, but life in his favor. This is argued for by Craigie in WBC and Dahood. It entails assuming the meaning death from the word רגע. A strength to this argument is the antithetical parallelism that would nicely subsume with this reading; however, in light of the larger context, I think it better to go with the traditional and more common rendering of the term רגע as meaning moment. After all, the consequence of the brevity of his anger is elucidated in the next two colas by the literally overnight transformation from sorrow to joy.
 The subject of the verb לין is personified as an actual guest who might come for visit and spend the night. Thus poet says that Mr. Weeping spends the night, but Mr. Joy is there to greet you in the morning. A beautiful picture of the transformation that God orchestrates for those who cry to him for help. Also, the beginning of each time period of visitation (i.e. evening and morning) is fronted here for constituent focus that the end results might be more starkly compared.