Adequate for teaching, rebuking, correcting and for instruction to equip the man of God for every good work.
Yep, that is what the Catholic church believes, holds as true and teaches.
What is doesn’t teach is that which is NOT found anywhere in Scripture and that is that the written Scripture is the only way one can teach, rebuke, correct or instruct. Also, that it is not the only way one can know of salvation.
Praise be to God for His Holy Word and praise be to God for His Holy Church to whom He entrusted the mission of proclaiming His Gospel to the whole world.
What other standard is there then? What did the Catholic church set up as necessary that God didn't include in Scripture?
Prove that a person NEEDs the EXTRA teaching of your chosen religion to attain these worthy goals and you've done a yeoman's job.