The nation that God is speaking of here is the bringing in of the New Testament ( Grace). The mighty men were the Apostles. They came speaking another tongue ( speaking in tongues) that the Old Nation ( OT. law) could not understand.
Their quiver was the word of God coming out of their mouth
Repent and be baptized in the name of Jesus for the remission of sin and receiving the Holy Ghost with the evidence of speaking in another tongue as the Spirit GAVE THE UTTERANCE.