Deuteronomy 4:12
11 You approached and stood at the foot of the mountain, a mountain ablaze to the sky above it and yet dark with a thick cloud. 12 Then the Lord spoke to you from the middle of the fire; you heard speech but you could not see anything—only a voice was heard. 13 And he revealed to you the covenant he has commanded you to keep, the Ten Commandments, writing them on two stone tablets. 14 Moreover, at that same time the Lord commanded me to teach you statutes and ordinances for you to keep in the land that you are about to enter and possess.
Acts 9:7
5 So he said, “Who are you, Lord?” He replied, “I am Jesus whom you are persecuting! 6 But stand up and enter the city, and you will be told what you must do.” 7 (Now the men who were traveling with him stood there speechless because they heard the voice but saw no one.) 8 So Saul got up from the ground, but although his eyes were open, he could see nothing. Leading him by the hand, his companions brought him into Damascus. 9 For three days he could not see, and he neither ate nor drank anything.
Notes and References
"... The description of Mt. Horeb as blazing with fire and enveloped in a black cloud in Deuteronomy 4:11 LXX (καὶ τὸ ὄρος ἐκαίετο πυρὶ ἕως τοῦ οὐρανοῦ σκότος γνόφος θύελλα) probably serves as the background to the similar description in Hebrews 12:18 (καὶ κεκαυμένῳ πυρὶ καὶ γνόφῳ καὶ ζόφῳ καὶ θυέλλῃ) of the same event at the same locale. Or again in Acts 9:7 the companions of Paul when Jesus appears to him are said to hear a sound, but do not see anyone. Similarly, at Deuteronomy 4:12 the theophany is described as involving hearing the sound of the words but not seeing a form. Even closer to Deuteronomy 4:12 is the accusation of Jesus against his audience, “You have not heard his voice at any time nor seen his form” at John 5:37 ..."
Witherington, Ben Torah Old and New: Exegesis, Intertextuality, and Hermeneutics (pp. 397-401) Fortress Press, 2018