It is not uncommon to find Evangelical apologists to cite Old Testament texts as “proof” of Sola Scriptura, notwithstanding this proving too much for their case (e.g. if the OT “proves” formal sufficiency of “Scripture,” the NT is unnecessary). However, there are many texts in the OT itself which show that the OT authors did not hold to any form of Sola Scriptura. One disproof of this errant doctrine is 2 Chron 29:25:
He stationed the Levites in the temple of the Lord with cymbals, harps and lyres in the way prescribed by David and Gad the king's seer and Nathan the prophet; this was commanded by the Lord through his prophets. (NIV)
We can conclude the following from this text:
(1) First, David, Gad, and Nathan were dead about 250 years at this point;
(2) Yet, they passed on a "commandment of the Lord" which was prescribed by God's prophets on how worship was to be conducted in the temple;
(3) That prescription and commandment of the Lord is nowhere found in the Old Testament Scriptures.
So what we have here is a clear OT refutation of the Sola Scriptura principle. Other OT texts refer to the non-canonical written and non-inscripturated oral tradition of prophets and seers that were held to be as authoritative as inscripturated revelation: e.g. 2 Chron 9:29; 12:15; 33:18-19; 35:4; 1 Sam 9:9; Isaiah 30:10; Jer 26:18; Zech 1:4-6; 7:7; 8:9.