Easton's Bible Dictionary (1897)
Often referred to in Scripture (Job 40:9; Ps. 77:18; 104:7). James and John were called by our Lord “sons of thunder” (Mark 3:17). In Job 39:19, instead of “thunder,” as in the Authorized Version, the Revised Version translates (ra’amah) by “quivering main” (marg., “shaking”). Thunder accompanied the giving of the law at Sinai (Ex. 19:16). It was regarded as the voice of God (Job 37:2; Ps. 18:13; 81:7; comp. John 12:29). In
answer to Samuel’s prayer (1 Sam. 12:17, 18), God sent thunder, and “all the people greatly feared,” for at such a season (the wheat-harvest) thunder and rain were almost unknown in Palestine.
Smith's Bible Dictionary (1863)
is hardly ever heard in Palestine form the middle of April to the middle of September; hence it was selected by Samuel as a striking expression of the divine displeasure toward the Israelites. (1 Samuel 12:17) Rain in harvest was deemed as extraordinary as snow in summer, (Proverbs 26:1) and Jerome states that he had never witnessed it in the latter part of June or in July. Comm. on (Amos 4:7) In the imaginative philosophy of the Hebrews, thunder
was regarded as the voice of Jehovah, (Job 37:2,4,5; 40:9; Psalms 18:13; 29:3-9; Isaiah 30:30,31) who dwelt behind the thunder-cloud. (Psalms 81:7) Thunder was, to the mind of the Jew, the symbol of divine power (Psalms 29:3) etc., and vengeance. (1 Samuel 2:10; 2 Samuel 22:14)
Hastings' Dictionary of the Bible (1898)
THUN'DER is very rare in Palestine from the middle of April to the middle of September. Hence it was a striking miracle when, in answer to Samuel's prayer, God sent thunder and rain in wheat-harvest (May 18 to June 15). 1 Sam 12:17. Thunder was regarded as Jehovah's voice. Job 37:2; Ps 18:13; Ps 81:7; Isa 30:30-31. When the people heard God's voice, they said that it thundered. John 12:29. Thunder accompanied the giving of the Law. Ex 19:16. It
was a symbol of divine power, implying possible vengeance upon wrong-doers. 1 Sam 2:10; 2 Sam 22:14; Isa 29:6; Rev 8:5.