For the LORD will not forsake his people, for his great name's sake, because it pleased the LORD to make you a people for himself. (1 Samuel 12:22)The reason God acts for us, is because he has decided not to forsake his people, not for our sake, but for his great name's sake. God will always be faithful to his people, because he is committed to his glory. Since he will never abandon his glory, he will always be committed to us. The best news for us is that he is faithful to his glory!
(For more on this idea, please check out John Piper's message called, "The Pleasure of God in His Name". The text from this message is from 1 Samuel 12:22)
Only fear the LORD and serve him faithfully with all your heart. For consider what great things he has done for you. (1 Samuel 12:24)Since we are assured of God's favour because of his commitment to His own glory, we can now respond in faithful service to our God. We need to remember the great things he has done for us. For us who know Christ, we have much to consider. God has done good things for us. Now let is fear him and serve Him faithfully with all our hearts.
I call this post a Summary of the Bible in Two verses because I think if you now look at the rest of the Bible through these lenses: God's commitment to his own glory, and our response to his goodness in obedience, it will help make sense of things, and give you a good framework for living the Christian life.
For myself personally, it would not be an overstatement to say that understanding these two things has changed my life.