The tree is known by its fruit. Those who profess to belong to Christ will be recognized by their actions. However, what matters now is not a mere professing of faith. Now the crucial thing is whether one is found in the power of faith to the end. He who truly possesses the word of Jesus can even hear his silence speak. In this way shall he be perfect: he will act in accordance with his words and will be known even by his silence.

Source: The Early Christians