Scripture thoroughly furnishes us.
2Tim 3:16-17 won't bear the weight usually placed upon it.
(1) It's referring to OT Scripture. If the OT is sufficient, the NT is superfluous. Right?
(2) It wasn't written to an entire congregation, just to an individual, because it is not in fact a message applicable to the whole church. See point #4.
(3) In fact, there was not a printing press till around 1500 A.D, which is one of the major thorns in Sola Scriptura.
(4) Who is it applicable to? It pertains to a 'man of God' (an OT designation for a PROPHET). OBVIOUSLY, only a prophet can RELIABLY divide rightly the Word of Truth. The rest of us are largely stabbing in the dark by comparison, as fallible exegetes.
(5) The passage is MERELY anticipatory ('hopeful'), because no one in this life will ACTUALLY be 'fully equipped' (perfect). However, prophethood vis a vis the written Word is certainly a step in the right direction.
(6) The Greek root word in that passage for teaching is DIDACTIC. Note well that ALL Scripture is didactic, according to that very passage. This presents a considerable challenge, hermeneutically, for the cessationist, in his attempt to disparage the book of Acts - and all charismatic passages - as non-normative. Cessationists, in a nutshell, cherrypick the Bible, in preference for what they WANT to believe, 'having a form of godliness, but denying the power thereof'.
Conclusion. 2Tim 3:16 lends no support to the cessationist thesis. On the contrary, it soundly refutes it. The need for a 'man of God' (prophets) is just as relevant today as it was back then.