Acts 2:3

Tongues... of fire. The Hebrews use the name tongue, for almost any thing pointed. Thus they say, a tongue of the earth, for a promontory. (Josue xv. 5.) A fiery tongue for a flame in shape of a tongue. (Isaias v. 24.) The expression, therefore, in this place, may mean noting more than sparks, or rather flames, which appeared above all who were in the house. --- Sed et Latinis quod extremum et acutum est lingua dicitur, quare scopulos summos & invios linguas dixit Cæsar. (Pastorini) --- By the fiery tongues is signified the efficacy of the apostles' preaching, and the gift of tongues bestowed upon them. (Menochius)