“And divided tongues as of fire appeared to them and rested on each one of them” (Acts 2:3)
Pentecost was a feast when the Jews offered burnt sacrifices of animals and bread made from new grain at the harvest (Leviticus 23:15-20). So when the flames of the Holy Spirit appeared on that feast day upon the twelve apostles, it seemed that they too were being offered up as burnt sacrifices.
The burning of offerings was a way to give them to God completely, and when the Holy Spirit came, he took total possession of the apostles. They were unharmed by the flames but their minds and hearts were filled with divine gifts, so they could preach the Gospel to the ends of the earth. The Holy Spirit wants to consume us with his fire too: he wants to take possession of us, which, paradoxically, is the only way we can be truly free.
