Charles Ellicott Commentary Acts 7:30

"And when forty years were fulfilled, an angel appeared to him in the wilderness of Mount Sinai, in a flame of fire in a bush." — Acts 7:30 (ASV)

There appeared to him in the wilderness.—With the exception of the substitution of Sina, or Sinai, for the less familiar Horeb, the fact is stated in nearly the same words as in Exodus 3:2. The reference to this revelation, besides the bearing it had on the main argument of the speech, was indirectly an answer to the charge that he had spoken “blasphemous words against Moses.” Both in the Hebrew and the Septuagint (LXX), the word “angel” is, as here, without the article.

In a bush.—The Hebrew word seneh is used for a species of thorny acacia, which still grows in the wilderness of Sinai. The Greek word, in the Septuagint (LXX) and here, was used commonly for the bramble, or any prickly shrub.