Albert Barnes Commentary Job 37:4

"After it a voice roareth; He thundereth with the voice of his majesty; And he restraineth not [the lightnings] when his voice is heard." — Job 37:4 (ASV)

After it a voice roars - After the lightning; that is, the flash is seen before the thunder is heard. This is apparent to all, the interval between the lightning and the hearing of the thunder depending on the distance. Lucretius, who has referred to the same fact, compares this with what occurs when a woodman is seen at a distance to wield an axe. The glance of the axe is seen long before the sound of the blow is heard:

Sed tonitrum fit uti post auribus accipiamus,
Fulgere quam cernunt oculi, quia semper ad aures
Tardius adveniunt, quam quae visum moveant res.
Nunc etiam licet id cognoscere, caedere si quem
Ancipiti videas ferro procul arboris actum.
Ante fit, ut cernas ictum, quam plaga per aures
Det sonitum: Sic fulgorem quoque cernimus ante.

Lib. vi.

He thunders with the voice of his excellency - That is, with a voice of majesty and grandeur.

And he will not stay them - That is, he will not hold back the rain, hail, and other things which accompany the storm, when he begins to thunder (Rosenmuller).

Or, according to others, he will not hold back and restrain the lightnings when the thunder commences. But the connection seems rather to demand that we should understand "them" as referring to the usual accompaniments of a storm: the wind, hail, rain, etc.

Herder renders it, “We cannot explore his thunderings.” Prof. Lee, “And none can trace them, though their voice be heard.” According to Lee, the meaning is that great and terrifying as this exhibition of God’s power is, the progress of these, his ministers, still cannot be followed by the mortal eye.

But the usual interpretation given to the Hebrew word is that of “holding back,” or “retarding,” and this idea accords well with the connection.