Create a New Heart
Paul was giving advice to two women having an argument. As his final piece of advice, he told them to create a treasury in their hearts. When people have an argument, they tend to over-focus on the details of the argument and every negative thing they can think of about the other person. Paul gave the antidote to that.
8 Finally, brethren, whatever is true, whatever is honorable, whatever is right, whatever is pure, whatever is lovely, whatever is of good repute, if there is any moral excellence and if anything worthy of praise, let your mind reckon those things as reality. (Phil 4:8)
As the final step of his instruction and probably the most important, he said to the two women to take what they have seen that is true, honorable, right, pure, and of good reputation, and anything that has moral virtue in it or is worthy of praise (probably involving the other person) and make that reality. The phrase “let your mind dwell on these things" literally means to make that your definition of reality. It is sometimes translated “reckon." So what does reckon mean? He said not to make argument and contention reality, but to make all of the gifts of God and spiritual beauty reality. Arguments sometimes are the shadows of sin in life and virtues are the solid realities of God. If our hearts dwell in the midst of those, we will live in a garden of spiritual pleasures and be naturally cheerful people. If we live in the midst of arguments and disputes, we will become naturally negative people. The home we build for our own hearts to inhabit should be one of beauty.