The doctrine of sola scriptura, with its teaching regarding the authority, completeness, perfection and sufficiency of Scripture, needs to be taught today with a renewed zeal and urgency. The reasons for this renewed zeal are not merely because of the current popularity of Romanism, Eastern Orthodoxy, modernism, neo-orthodoxy, the cults, the charismatic movement and the church growth movement. The chief reason is the current declension among the conservative Reformed and Presbyterian denominations today, particularly in the area of worship. Not only are many Reformed and Presbyterian churches allowing human innovations in worship, but the regulative principle of Scripture, and the correlative doctrine of the sufficiency of the Bible in all matters of faith including worship, is openly rejected by many pastors and elders. The regulative principle of worship (which is sola scriptura applied to the worship conducted by the church) is one of the greatest achievements of the Calvinistic reformation. In order to shore up the foundation of Reformed worship we must go back to the doctrine of sola scriptura. We pray that this study will be used for the reformation of the church.