The plain Hebrew of Exodus 24:17 says that the appearance of the glory of the Lord was like devouring fire on the top of the mountain in the eyes of the children of Israel. The Targum Pseudo-Jonathan sharpens the image and sharpens the response.
The splendor of the glory was as burning fire with flashes of devouring fire. Two fires in one. The steady burn that does not consume, and the sudden flash that devours. The Targum insists they are both present at once, layered, alive. And the reaction of Israel is no longer silent observation. The sons of Israel beheld and were awe-struck. The Aramaic verb carries the sense of trembling. They did not simply see. They were shaken by what they saw.
This is the theological knife-edge of Sinai. The fire that revealed the Torah was the same fire that, in a different moment, would consume Nadab and Abihu. It was the same fire that would later fall on Elijah's altar at Carmel. The glory of the Holy One is not one thing. It is both nourishment and judgment, the flame that warms and the flame that burns.
The Rambam in the Mishneh Torah teaches that the soul's love of God must include the fear of God, or it is not yet love. The Targum's double fire is the visual proof. What Israel saw on Sinai was exactly that: a devotion that demands reverence, a nearness that refuses to become cheap.
The takeaway the old rabbis pressed: do not imagine that awe and love are opposites. At Sinai they arrived together, in a single burning.