John Trapp on Isaiah 7:20

Ver. 20. In the ſame day ſhall the Lord ſhave] Not ſhear but ſhave, with a razor, to ſet forth the calamity of war which waſteth and taketh away all, and maketh clean work, as we uſe to ſay: nihil in toto regno intactum reliquit, ſed omnia à ſummo ad imum expilavit Aſſyrius. The Aſſyrian is here called Gods razor, becauſe his inſtrument to ſhave as he pleaſeth: though haply by exceeding his commiſſion, as Zach. 1.15. he might prove a deceitful razor, as Pſal. 52.2. that inſtead of ſhaving the hair, lanceth the fleſh.

That is hired] Whether by Ahaz himſelf, but for a better purpoſe, 2 King. 16.7, 8. not to hurt but to help, though it fell out otherwiſe: or by God, who paid the Aſſyrian for his hire the Lands of Iſrael and of Syria: ſee the like Ezek. 29.18, 19. Barbers uſe not their razors but for reward.

Beyond the river] Euphrates that ran between Syria and Aſſyria, but could not keep off the Aſſyrian Deſtroyer.

The head, and the hair of the feet] Elſewhere called head and tail, that is, high and low, Prince and Peſant.

And it ſhall alſo conſume the beard] 1. the Prieſts, Pſal. 133.2. as ſome ſenſe it: or, as others, all the comelineſs and virility of the Jewiſh nation.