“fire came out from before Yahweh.” This is God lighting the fire upon the altar of sacrifice in front of the Tent of Meeting. God initially lights the fire of the Tent of Meeting which Moses had just built, then the priests are never to let that fire go out. The perpetual fire on the altar is the fire of God. God lit the Tabernacle altar with fire, which is why the Levites were told to keep the fire going and never let it go out (Lev. 6:12, 13). God accepted Gideon’s offering with divine fire (Judg. 6:21). Elijah’s sacrifice was accepted by fire from heaven (1 Kings 18:38), as was David’s (1 Chron. 21:26). God also lit the fire on the altar of the Temple with fire from heaven (2 Chron. 7:1-3). The Jewish audience collected there at the Temple on the Day of Pentecost understood all this, and had the opportunity to see that God (and His Messiah) accepted the Apostles.