"And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance" (Acts 2:3, 4). The Holy Spirit, assuming the form of tongues of fire, rested upon those assembled. This was an emblem of the gift then bestowed on the disciples, which enabled them to speak with fluency languages with which they had heretofore been unacquainted. The appearance of fire signified the fervent zeal with which the apostles would labor and the power that would attend their work.
"There were dwelling at Jerusalem Jews, devout men, out of every nation under heaven" (verse 5). During the dispersion the Jews had been scattered to almost every part of the inhabited world, and in their exile they had learned to speak various languages. Many of these Jews were on this occasion in Jerusalem, attending the religious festivals then in progress. Every known tongue was represented by those assembled. This diversity of languages would have been a great hindrance to the proclamation of the gospel; God therefore in a miraculous manner supplied the deficiency of the apostles. The Holy Spirit did for them that which they could not have accomplished for themselves in a lifetime. They could now proclaim the truths of the gospel abroad, speaking with accuracy the languages of those for whom they were laboring.
This miraculous gift was a strong evidence to the world that their commission bore the signet of Heaven. From this time forth the language of the disciples was pure, simple, and accurate, whether they spoke in their native tongue or in a foreign language.--The Acts of the Apostles, pp. 39, 40. YRP 204
How can we honor God, how can we vindicate his word, unless we are much in prayer, appealing to him to manifest his power in behalf of the perishing? Pr 42
And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language. And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans? And how hear we every man in our own tongue, wherein we were born? Acts 2:5-8 (King James Version)