The mention of an angel is a metaphorical way of speaking about the presence of God in the bush (see Exodus 3:2–6).1 Similar to the giving of the law at Sinai, the Jews considered the Lord to be too holy to appear to a man and thus assumed that his revelation was mediated by an angel. An important point that Stephen wants to make here is that the revelation which led to Israel’s salvation from Egypt was given in the desert and not in Jerusalem.2
30 Quarante ans plus tard, un ange lui apparut, au désert de la montagne de Sinaï, dans la flamme d'un buisson en feu.