Recall verse 16: The scriptures are the canon or standard by which we should measure the worth of all things. If our sources of information and influence do not measure up to what is written in the scriptures, it must be “because there is no light in them.” Thus, verse 20 outlines the first test of any revelation: Does it speak the word of the Lord, or is it filled with light? A second test: Is it in harmony with the teachings of the only man on earth called and authorized to speak for the Lord in everything—the president of the Church? (D&C 43:1–7; 132:7). A third test: Does it come by the Holy Ghost, and can it be felt in the heart? (2 Nephi 33:1; D&C 50:17, 23; 100:5–8).