Verses 13-15 contain a complaint of the people about the difficulty of God's way. They see things within the nation that are unfair. Those who are really assertive and aggressive, those with a lot of carnal drive and energy, are getting ahead. "What good is it to be godly?" they ask. God replies to them with a promise in verses 16-17. He does not say that He would end the injustice right then.
God shows that His ear is on our conversations. Psalm 139 tells us that His Spirit goes everywhere! He is aware. He is not really judgmental, but He is aware of what is happening, and He wants to encourage us to grow.
This instruction is intended for the church at the time of the end, to encourage those who are genuinely trying to be faithful to God yet who feel frustrated and doubtful because of what they see going on around them. So God replies with this encouragement to those who speak on His name. This refers to those who have the Word of God in their minds and hearts and are speaking to one another about the wonderful fellowship with God we have been drawn into. They are tying God into all aspects of their lives.
God says He is making a book of remembrance, and He will reward these people for their faithfulness. It is obvious that what these people are meditating on and talking about is God's name and what is contained within their hearts, and it is good. This reveals a major purpose for the Sabbath: to get God's Word into our hearts, minds, and consciences. He is a part of our lives, and we need to think about Him being a part of them. Do we see God? That is what this is about. Do we see Him as a part of our lives? Do we see Him as a part of our futures? When we do, then we find ourselves talking about it.