Read 2 Timothy 3 at Bible Gateway.
The rest of 2 Tim 3 forms a separate chiastic structure (the structure for 2 Tim 3:1-13 is posted here):
2 Tim 3:14-17
1a) 2 Tim 3:14, Continue in that which you learned + been assured of;
1b) 2 Tim 3:15a, From childhood you have known the Holy Scriptures;
central axis) 2 Tim 3:15b, Making wise for salvation through faith which is in Christ Jesus;
2b) 2 Tim 3:16, All Scripture is given by inspiration of God + profitable for instruction in righteousness;
2a) 2 Tim 3:17, That the man of God may be complete.
2 Timothy 3:16
Paul is saying something amazing about Timothy: that he has known the Holy Scriptures from childhood, which made him wise for salvation through faith in Christ Jesus. Of course, the Holy Scriptures that Paul is talking about is the Old Testament, for that was the only Scriptures the church had at first, the New Testament not having been written yet.
Since the Old Testament teaches salvation by grace through faith, the same gospel as the New Testament, and since Moses wrote about Jesus (Joh 5:46), it makes sense that knowing and believing all the Old Testament Scriptures from childhood prepares someone to receive salvation through faith. Paul hints at the same here:
Therefore the law was our tutor to bring us to Christ, that we might be justified by faith. Gal 3:24
The Law serves an integral purpose to prepare a person to receive Christ through faith. There is such a problem in our churches of raising our children to remain in the faith upon reaching adulthood. We don’t teach the authority and truth of the Law and the Old Testament to our children in our churches, and losing our children is the fruit this lapse is bearing.
Jesus even boldly says:
“For if you believed Moses, you would believe Me; for he wrote about Me. But if you do not believe his writings, how will you believe My words?” Joh 5:46-47
Beloved, God is smarter than we are, and His instruction to parents, particularly fathers, is:
“And these words which I command you today shall be in your heart. You shall teach them diligently to your children, and shall talk of them when you sit in your house, when you walk by the way, when you lie down, and when you rise up. You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes. You shall write them on the doorposts of your house and on your gates.” Deu 6:6-9
God is speaking here particularly of the Torah. He knows that our children need this intimate knowledge and authority of the Law in order to bring them to Christ, in order to make them wise for salvation through faith. Believers, and especially fathers, we must repent of our anti- Torah and anti- Old Testament bias which is not a bias taught by Scripture, but learned from man. We must repent of claiming to be wiser than God and embracing the foolishness of man over the wisdom of God (1 Cor 1:20-21). We must repent of rejecting Genesis, Torah, and the Old Testament, and once again embrace the wisdom of God and the word of God, and teach its authority, and obey its authority from the very first verse. If the generation of the parents repent and obey (Deu 30:1-6), they will see the generation of the children be raised up in wisdom and faith in Christ Jesus.