When Jesus instructed his followers from the mountain, he instructed them on their inner life. Merely religious people tend to practice their religion before others to be admired by them for their righteousness. However, Jesus’ followers cultivate an inner righteousness by following Jesus when no is there to see them, because they understand that true righteousness is developed in a relationship with Jesus and their heavenly Father. In this way righteous living flows out of them, because they they think righteous thoughts, producing naturally righteous speech and behavior. We might say that they become fluent in righteousness, much like we become fluent in a second or third language. When we learn another language we have to practice it. When we are first beginning we tend to equate the new language with the one we know, but as time goes by, we discover that we begin to think in that new language so that we begin to speak fluently. Following Jesus, learning to think like he thinks will over time and practice naturally produces speech and behavior that imitates Jesus so that whether we are in public or alone, our thoughts and actions are consistent.
To this end, Jesus instructed his followers to practice their acts of mercy out of the public eye and to retreat to a quiet spot alone with God to converse with their heavenly Father. While Jesus addressed behaviors in his mountain-top lesson, the apostle Paul addressed the inner aspects of what we do in private when he instructed the Corinthians to bring every one of their thoughts in alignment with Jesus’ thoughts. If we fail to practice Paul’s lesson, we will be conflicted as we work to apply what Jesus taught. In agreement with Paul, Jesus said that our speech flows from what is already in our heart. So to change our speech and behavior we must address the condition of our heart. To address the condition of our heart, we must be in relationship with Jesus and our heavenly Father through the presence of the Holy Spirit.