Psalm 2/Notes/Verbal.v. 4.810689

The yiqtol verbs in vv. 4-5 narrate a sequence of events: first YHWH laughs/mocks (v. 4) and "then" (אָז) he speaks to them (v. 5a) so that they are terrified (v. 5b). This sequentiality is strengthened by the presence of אָז (v. 5a) (on this function of אָז see e.g., BHRG §40.6.2). The use of yiqtol (vs qatal and wayyiqtol) has the effect of making it more like a performance; it makes it feel as though the events are happening right before the speaker's eyes (e.g., think of a sports commentator saying, "he shoots, he scores!").