1 Nephi 20:5-6

In verse 5, we find that Isaiah is speaking of God and of the house of Israel. From the footnote, 5a, I believe that Isaiah is saying that God is all-knowing and can tell that you, house of Israel, are worshiping idols. In the next verse, I believe the Lord is saying to the house of Israel that He has shown them new things, perhaps even some of His mysteries and they have not proclaimed them. The footnote, 6a, refers to 1 Corinthians 9:16, where Paul is saying that woe is unto him if he doesn't preach the gospel! So, as an application to our day, we can see that there is a great necessity to not worship idols, which can even be material things and sports (moderation is okay, but make sure it is just that and not more), and preach the gospel. Make sure you pray for missionary experience and open your mouth when you are prompted to share the gospel. I need to work on these things as much as anyone else, but I feel that it is important to keep it in the front of our minds.