John Trapp on Jeremiah 4:2

Ver. 2. And thou ſhalt ſwear The Lord liveth] Not by Baal ſhalt thou ſwear, or other Idols, but by the living God, or by the life of God. The Egyptians once ſware by the life of Pharaoh, as the proud Spaniards now do by the life of their King. But, to ſpeak properly, none liveth but the Lord: and none ſhould be ſworn by but he alone; an oath being a proof of the Divine Power, which one worſhippeth. The Pythagoreans uſed to ſwear by [non-Latin text not transcribed], Quaternity, which they called [non-Latin text not transcribed] the fountain of eternal being: and this doubtleſs was the ſame with [non-Latin text not transcribed] Jehovah.

Tremel. In truth, in judgement and in righteouſneſſe] Vere, ritè & juſte. 1. In truth, Rom. 9.1. that is, 1. To that which is true, leaſt we fall into perjury, Lev. 19.12. And, 2. Truly, agreeable both to the intentions of our mind (not deceitfully, Pſal. 24.2.) and agreeable alſo to the intentions of him that miniſtreth the oath, and not with mental reſervations, as Romiſh Prieſts oft ſwear.

The Romans uſed that moſt conſiderate wo[illegible: 1 letter]d Arbitror, when the Jurors ſaid thoſe things which they knew moſt certainly. Suidas. In judgement] Or, conſiderately, duely weighing the conditions and circumſtances: not raſhly and unadviſedly, Levit. 5.4. 1 Sam. 14.39. as thoſe that ſwear in heat and choler, ſwear when they ſhould fear, Deut. 10.20. and 28.58. The Graecians when they would ſwear by their Jupiter, out of the mere dread and reverence of his name forbore to mention him. And the Egyptians bore ſuch reſpect to Mercurius Triſmegiſtus, that they held it not lawful to pronounce his name lightly and raſhly. This is check to many ſwearing Pſeudo-Chriſtians. Such alſo as ſwear in jeſt, will (without repentance) go to hell in earneſt. The ancient form of taking and impoſing an oath was, Give glory to God, Joſh. 7.19. Joh. 9.24.

And in righteouſneſſe] 1. Promiſing by oath, lawful and poſſible things only; not making an oath a bond of iniquity, 1 Sam. 25.21, 32. and 28.10. 2. Careful to perform what we have ſworn, though to our own hindrance, Pſal. 15.4.

And the Nations ſhall bleſſe themſelves in him] Or ſhall be bleſſed in him, that is, in that God to whom thou returneſt, and by whom thou thus ſweareſt. They ſhall turn to God by thine example, and hold themſelves happy in ſuch a good turn.