Flee also youthful lusts: but follow righteousness, faith, charity, peace, with them that call on the Lord out of a pure heart. II Timothy 2:22

In this passage we see Paul’s admonition to Timothy to grow in his maturity in the faith. Later in his letter he points Timothy to the source of that maturity.

All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, throughly furnished unto all good works. II Timothy 3:16,17