Habakkuk 2:14 (NKJV) For the earth will be filled With the knowledge of the glory of the Lord, As the waters cover the sea.
Colossians 1:9 For this reason we also, since the day we heard it, do not cease to pray for you, and to ask that you may be filled with the knowledge of His will in all wisdom and spiritual understanding;
To be Filled with the knowledge of God and the understanding of the Word will open our life to a new level of living and offering. We being convinced with the Word of God meaning truly bealiving in it will cause us to do good not for the good that will come back to us but for the sake of it.
But this will require us a new level of lowliness as God do not just give great understanding to people who are wicked and crooked. God bestow understanding and WISDOM to people who are humble and righteous and are capable of managing and using the gift of a good mind with care.
This is what it means to have a new heart. As we know the bible talks a lot about heart and that the human heart is fundamentally broken and we need a new heart as the Prophet Jeremiah said. The bible talks about people having joy in their hearts or plan evil and deceit in their hearts, and also to understand with your heart. But as we know the heart does not think or feel, it is an organ right to the left of our chest that pumps blood to the whole body.
But the people back then probably didn’t know much about the brain, so they think that all the human emotions, will and thoughts are the workings of the heart. So now that we know that the heart mentioned int many ancient literature relate to the mind. We can safely say that the renewal of ones heart is the renewal of ones mind with the understanding of the Word.