Apollinary Vasnetsov’s The City Area of 17th Century (no date)
One can be numbered among the Christians, yet not be a Christian. Everyone knows this. There is a moment which stands out sharply in our life, the moment when the distinguishing features of the Christian life begin to be a part of him. Christian life is zeal: the strength to live in communion with God through our faith in our Lord Jesus Christ, with the help of God’s grace, and through actively doing His holy will to the glory of His holy name.
The essence of the Christian life consists in communion with God in our Lord Jesus Christ. At first this communion is usually hidden not only from others, but also from oneself. It cannot be seen or sensed within us. It proves its presence simply by a fire of zeal to please God in a Christian way of utter selflessness, combined with a loathing for everything that opposes this.
~St Theophan the Recluse

In the center of the painting is a fool-for-Christ – always an example of “fire of zeal to please God in a Christian way…”