Once you were alienated and hostile in your minds because of your evil actions.
The power of our mind cannot be gainsaid. Paul continues to emphasize how important what goes on in our mind (heart) is. When our mind is hostile to God it produces evil actions which work to separate us from truth and grace. When it is filled with wisdom, spiritual understanding and knowledge of God it serves to keep us in Gods will and produce good works. The emphasis of Scripture on our mind is striking. We have a tendency to put so much emphasis our feelings; yet, Scripture does not do such. God has given us a mind and longs to fill it with Himself so that we might know true truth and true love as He has defined them. He has reconciled us by His death and has given us the gift of knowing and being able to rise above whatever feelings we have to an understanding of our blamelessness in Christ. Not so that we can take some sort of personal satisfaction but so that we can revel in Christ -holding fast the faith He has given through the strengthening of our minds and the purification of our souls.