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.[2.?]) 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 Cęsar. (Pastorini) — By the fiery tongues is signified the efficacy of the apostles’ preaching, and the gift of tongues bestowed upon them. (Menochius)

2. Here is a visible sign of the gift they were to receive. They saw cloven tongues, like as of fire (v. 3), and it sat—ekathise, not they sat, those cloven tongues, but he, that is the Spirit (signified thereby), rested upon each of them, as he is said to rest upon the prophets of old. Or, as Dr. Hammond describes it, "There was an appearance of something like flaming fire lighting on every one of them, which divided asunder, and so formed the resemblance of tongues, with that part of them that was next their heads divided or cloven." The flame of a candle is somewhat like a tongue; and there is a meteor which naturalists call ignis lambens—a gentle flame, not a devouring fire; such was this. Observe,

We have here an account of the public notice that was taken of this extraordinary gift with which the disciples were all on a sudden endued. Observe,

the apostles themselves not expecting it, to prepare them to attend the more unto what they should hear and see afterwards; also to signify the unexpected and powerful progress which the gospel should have: it may be, to cause the greater concourse to that place, it being a usual manner; and God would make this miracle more public. to show that the Spirit should be bestowed on them that were met there, and on all the church throughout the world.

Verses 1-4 We cannot forget how often, while their Master was with them there were strifes among the disciples which should be the greatest; but now all these strifes were at an end. They had prayed more together of late. Would we have the Spirit poured out upon us from on high, let us be all of one accord. And notwithstanding differences of sentiments and interests, as there were among those disciples, let us agree to love one another; for where brethren dwell together in unity, there the Lord commands his blessing. A rushing mighty wind came with great force. This was to signify the powerful influences and working of the Spirit of God upon the minds of men, and thereby upon the world. Thus the convictions of the Spirit make way for his comforts; and the rough blasts of that blessed wind, prepare the soul for its soft and gentle gales. There was an appearance of something like flaming fire, lighting on every one of them, according to John Baptist's saying concerning Christ; He shall baptize you with the Holy Ghost, and with fire. The Spirit, like fire, melts the heart, burns up the dross, and kindles pious and devout affections in the soul; in which, as in the fire on the altar, the spiritual sacrifices are offered up. They were all filled with the Holy Ghost, more than before. They were filled with the graces of the Spirit, and more than ever under his sanctifying influences; more weaned from this world, and better acquainted with the other. They were more filled with the comforts of the Spirit, rejoiced more than ever in the love of Christ and the hope of heaven: in it all their griefs and fears were swallowed up. They were filled with the gifts of the Holy Ghost; they had miraculous powers for the furtherance of the gospel. They spake, not from previous though or meditation, but as the Spirit gave them utterance.