This document is a summary of a sermon on developing a pure heart based on the sixth Beatitude from Matthew 5:8 - "Blessed are the pure in heart, for they will see God." The sermon discusses how purity starts from within by controlling thoughts and desires. It notes evil desires lead to temptation and sin. It also discusses diagnosing an impure heart through actions like making inappropriate insinuations. The sermon concludes by urging listeners to pursue righteousness wholeheartedly and take every thought captive for Jesus Christ.