אַחֲרָ֤יו ׀ יִשְׁאַג־ק֗וֹל יַ֭רְעֵם בְּק֣וֹל גְּאוֹנ֑וֹ וְלֹ֥א יְ֝עַקְּבֵ֗ם כִּֽי־יִשָּׁמַ֥ע קוֹלֽוֹ׃
그 후에 음성을 발하시며 위엄의 울리는 음성을 내시고는 그 음성이 들릴 때에 번개 빛을 금치 아니하시느니라
Rashi
In its wake [i.e., in the wake] of that light, the thunder roars, and it thunders with the voice of its pride. Those are the lightnings and the thunders, which bring the rain.
Malbim
According to Malbim, the thunder is emitted first, before the lightning. There are two possible reasons as to why they are observed in the reverse order: (i) whereas the sense of sight reacts instantaneously to light, the sense of hearing only reacts to sound after a short lapse of time; (ii) because the sound of the thunder reaches the observer after the flash of light from the lightning. It is unclear which explanation Malbim believed to be correct. Whatever, if the thunder was heard as soon as it was emitted, there would be no time-lag between them.
Rashi
and He will not cut them off The Omnipresent [will not cut off the thunder and the lightning].
Rashi
He will...cut them off Heb. יעקבם, He will cut them off, [and in the language of the Mishnah we learned (Sotah 16a): in three instances, the halachah supplants (עוקבת) the text].