Psalm 68:33 New English Translation

³³to the one who rides through the sky from ancient times.^[a]
Look! He thunders loudly.^[b]

Psalm 68:33 tc Heb “to the one who rides through the skies of skies of ancient times.” If the MT is retained, one might translate, “to the one who rides through the ancient skies.” (שְׁמֵי [sh^eme, “skies of”] may be accidentally repeated.) The present translation assumes an emendation to בַּשָּׁמַיִם מִקֶּדֶם (bashamayim miqqedem, “[to the one who rides] through the sky from ancient times”), that is, God has been revealing his power through the storm since ancient times.
Psalm 68:33 tn Heb “he gives his voice, a strong voice.” In this context God’s “voice” is the thunder that accompanies the rain (see vv. 8-9, as well as Deut 33:26).

New English Translation (NET)