Boyd’s Bible Dictionary:

(sound). Rare in Palestine, hence regarded as God’s displeasure (1 Sam. 12:1717Is it not wheat harvest to day? I will call unto the Lord, and he shall send thunder and rain; that ye may perceive and see that your wickedness is great, which ye have done in the sight of the Lord, in asking you a king. (1 Samuel 12:17)); Jehovah’s voice (Job 37:22Hear attentively the noise of his voice, and the sound that goeth out of his mouth. (Job 37:2); Psa. 18:1313The Lord also thundered in the heavens, and the Highest gave his voice; hail stones and coals of fire. (Psalm 18:13); Isa. 30:30-3130And the Lord shall cause his glorious voice to be heard, and shall show the lighting down of his arm, with the indignation of his anger, and with the flame of a devouring fire, with scattering, and tempest, and hailstones. 31For through the voice of the Lord shall the Assyrian be beaten down, which smote with a rod. (Isaiah 30:30‑31); John 12:2929The people therefore, that stood by, and heard it, said that it thundered: others said, An angel spake to him. (John 12:29)); symbol of divine power (Ex. 19:1616And it came to pass on the third day in the morning, that there were thunders and lightnings, and a thick cloud upon the mount, and the voice of the trumpet exceeding loud; so that all the people that was in the camp trembled. (Exodus 19:16); 1 Sam. 2:1010The adversaries of the Lord shall be broken to pieces; out of heaven shall he thunder upon them: the Lord shall judge the ends of the earth; and he shall give strength unto his king, and exalt the horn of his anointed. (1 Samuel 2:10); 2 Sam. 22:1414The Lord thundered from heaven, and the most High uttered his voice. (2 Samuel 22:14); Isa. 29:66Thou shalt be visited of the Lord of hosts with thunder, and with earthquake, and great noise, with storm and tempest, and the flame of devouring fire. (Isaiah 29:6); Rev. 8:55And the angel took the censer, and filled it with fire of the altar, and cast it into the earth: and there were voices, and thunderings, and lightnings, and an earthquake. (Revelation 8:5)).

Concise Bible Dictionary:

This is of rare occurrence in Palestine, and is regarded in scripture as being the voice of God in power, both in the Old Testament of the past and in the Revelation of the future (Psa. 29; Psa. 77:1818The voice of thy thunder was in the heaven: the lightnings lightened the world: the earth trembled and shook. (Psalm 77:18); Psa. 104:77At thy rebuke they fled; at the voice of thy thunder they hasted away. (Psalm 104:7); Rev. 4:55And out of the throne proceeded lightnings and thunderings and voices: and there were seven lamps of fire burning before the throne, which are the seven Spirits of God. (Revelation 4:5); Rev. 6:11And I saw when the Lamb opened one of the seals, and I heard, as it were the noise of thunder, one of the four beasts saying, Come and see. (Revelation 6:1); compare also John 12:2929The people therefore, that stood by, and heard it, said that it thundered: others said, An angel spake to him. (John 12:29)). In Psalm 78:4848He gave up their cattle also to the hail, and their flocks to hot thunderbolts. (Psalm 78:48), in recounting the plagues of Egypt, the flocks are represented as being consumed by HOT THUNDERBOLTS. The word is resheph, and is also translated “coals,” “burning coals,” “burning heat.” Doubtless lightning is referred to, as when the “fire of God” fell from heaven and burnt up Job’s sheep (Job 1:1616While he was yet speaking, there came also another, and said, The fire of God is fallen from heaven, and hath burned up the sheep, and the servants, and consumed them; and I only am escaped alone to tell thee. (Job 1:16)).