There are three spheres of privilege and responsibility Christians have in the house of God—priesthood, gift, and office.
As to the priesthood of believers, the book of Revelation teaches us that all Christians are “priests unto God,” and that they have been made so by the finished work of Christ on the cross (Rev. 1:6; 5:10). The Apostle Peter confirms this, stating that we are “an holy priesthood” who have the privilege to “offer up spiritual sacrifices, acceptable unto God by Jesus Christ” (1 Peter 2:5, 9). Since we are all priests, the epistle to the Hebrews exhorts Christians as a whole to approach God within the veil (in the holiest of all), and to engage in something that only priests can do (Heb. 10:19-22). Such an exhortation would not be given to any but those who are priests. Moreover, the fact that this epistle says that the Lord is “an High Priest” implies that there is a cast of priests under Him.
Since Scripture teaches that all Christians are priests, and that all brothers have an equal privilege to exercise their priesthood publicly in the assembly, in meetings for worship and prayer, we simply need to wait on the Spirit of God to lead out the prayers and praises of the saints. If we allow Him to lead in the assembly, in the place that is rightfully His, He will lead a brother here and another there to audibly express worship and praise as the mouth-pieces of the assembly. Of course, the exercise of priestly functions are not confined to the assembly but can be exercised privately as well—in any place and at any time.