In Scripture truth is both said to necessarily dwell in us in Jesus, and we in the truth (as found in Scripture and in Jesus). Truth must become nothing less than a part of us.
Head knowledge can be both underrated and overrated. It's important that we keep working at loving God with all our minds, along with all the rest of us. But head knowledge alone is not enough. We must work the truth of God in Jesus into our lives. We must seek to live out the truth as it is in Jesus. Both individually in our private and public lives, and together with other people in Jesus in this world.
Christians are notorious for professing truth yet not living it out well. Hypocrisy is the word here. This is why we're to keep working at getting rid of all deceit in our lives. The truth of God in Jesus we find throughout Scripture can help expose us so that we can deal with the lies in our life. If my heart is moved in a certain direction away from God's will then I must repent and believe in God's deliverance for me in Jesus. It's important to see not only the truth exposing us, but the grace of God in Jesus bringing forgiveness, cleansing and new life. Grace and truth together in Jesus is what can change us. Only by grace can truth become a part of us.
Of course this is ongoing. We don't arrive in this life, and we do need both private and corporate confession of our sins.
Sometimes I grow weary of what I know is wrong inside of me. I know that my heart or my life is not measuring up with the truth revealed in Scripture. Sometimes I can feel as hopeless as humankind in Adam, rhetorically depicted in Romans 7. But I must not give in to that. We're not in Adam, but in Christ. It's a matter of life and nothing directly to do with how we're feeling or not feeling. And it's available to us through God's grace for us in Jesus. And it takes time; this is ongoing.
What might you like to add to my meandering thoughts on this, here?