1 Chron. 15 [The Message]
King David required the Levites to make proper preparation to bring the Ark back to Zion. His failure to employ the proper tribe resulted in the death of Uzza. It was a bitter lesson to learn. It motivated him to seek the due order for moving the Ark. Proper preparation was made.
For New Testament worship leaders and musicians, proper preparation is also important. Yes, our sincerity is vital, but to approach the God of the Universe with no preparation can be construed as presumption. In my opinion, the worship leaders should have skill and do rehearsals. Above all, the integrity and spiritual preparation they offer is critical to sustaining a praise and worship ministry that pleases God and inspires the saints. Our preparation is giving God a house to live in, our lives a spiritual sacrifice.
Thou art holy, O Thou that inhabitest the praises of Thy people. [Ps. 22:3]