Psaumes 2:1

Why have nations gathered Our Sages (Ber. 7b) expounded the passage as referring to the King Messiah, but according to its apparent meaning, it is proper to interpret it as referring to David himself, as the matter is stated (II Sam. 5:17): “And the Philistines heard that they had anointed David as king over Israel, and all the Philistines went up to seek, etc.,” and they fell into his hands. Concerning them, he says, “Why have nations gathered,” and they all gathered.

and kingdoms think vain things in their heart.

and kingdoms Heb. ולאמים. Menachem interprets לאמים, אמות, and גוים as all closely related.

Why do nations assemble (לָ֭מָּה רָגְשׁ֣וּ - lamah ragshu): What seems correct in my eyes is that this psalm was composed by one of the poets concerning David on the day he was anointed. Therefore, it is written [later in verse 7], "This day I have begotten you." Or [alternatively, the psalm is] about the Messiah.

And ragshu [translated here as "assemble," but can also mean rage/tumult] is like "joined together" (chavru). Similar to it is [the phrase in (Psalm 64:3)] "from the assembly/tumult (mirgeshet) of the workers of iniquity."

And the Lamed [prefix] of le'umim (לְאֻמִּ֗ים - peoples): [This Lamed is part of the] root [of the word], as the singular form is le'om (people/nation). As in (Genesis 25:23): "and one people (u-le'om) shall be stronger than the other people (mi-le'om)."

Plot/utter vain things (יֶהְגּוּ־רִֽיק - yehgu rik): [This refers to plotting] through speech (be-dibur). Similar [usage of hagah for speech is found], as in [verses like (Psalm 35:28)] "And my tongue shall speak (tehgeh) Your righteousness." And the [specific vain] speech [they utter] is [revealed in verse 3]: "Let us break their bonds asunder."

Why do the nations rage: – The Psalm is the second; and so we find it in all the more accurate books, that (these words) are the beginning of a Psalm. And in enumeration they inscribe it as the second. But some of our teachers have said (Babli, Berakhoth 9b) that Happy is and why do the nations rage form a single Psalm. And they have said (ibid. 10a) “Every section which was (specially) dear to David, he opened and closed with ‘Happy is (are).’ And this section he opened with ‘Happy is the man,’ and closed with ‘Happy are all they that put their trust in Him.’” The reason why this Psalm follows immediately the other is not known to us; nor why he arranged them in the order in which they are connected, for they are not arranged in historical order. For instance, the third Psalm is concerned with the affair of Absalom, and after it occur many Psalms whose subject-matter is earlier by a considerable period than the incident of Absalom. Notice also, at the end of the book, Psalm cxlii., “When he was in the cave; a Prayer,” (has reference to events) in the days of Saul. Therefore we cannot explain the arrangement of the Psalms according to the historical order.David composed and recited this Psalm in the opening of his reign, when the nations were gathered against him, as it is said (2 Sam. 5:17) “and when the Philistines heard that they had anointed David king over Israel all the Philistines went up to seek David.” And this is his meaning in saying Why do they tumultuously assemble (רגשׁו)? because all the Philistines had come up. And רגשה has the sense of gathering and great multitude, as (Ps. 64:3), “from the throng (רגשתי) of the workers of iniquity;” and the Targum of the passage (Ez. 30:10) “I will also make the multitude (המון) of Egypt cease,” is, “and I will make of no avail the raging (איהרגושת) of Egypt.”

And the peoples imagine a vain thing? – for when they came to make war they were saying proud things, because they had conquered Israel in the wars of Saul, and Saul and his sons were dead, and the people had been severely smitten. And from Saul's death until now there had not been another king for Israel. And he says, a vain thing is (the sum of) all their words.