A couple days ago I was in a discussion with my brother and a good friend about what is known theologically as "soteriology". That fancy word just means the study of the doctrine of salvation. We were discussing the role of reason and faith in our salvation, and also asking questions about how old someone needs to be in order for their profession of faith to be efficacious. I think 2 Timothy 3:14-17 is germane to our discussion.
But as for you, continue in what you have learned and have firmly believed, knowing from whom you learned it 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. All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be competent, equipped for every good work.