15 and how from infancy you have known the Holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus.

Read 2 Timothy 3:15 Using Other Translations

And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.
and how from childhood you have been acquainted with the sacred writings, which are able to make you wise for salvation through faith in Christ Jesus.
You have been taught the holy Scriptures from childhood, and they have given you the wisdom to receive the salvation that comes by trusting in Christ Jesus.