Genesis 20, 21 & 22; Matthew 7
Today we see God's faithfulness. His faithfulness in keeping promises, His faithfulness to provide and His faithfulness when we fail Him.
In Genesis 20 we once again see Abraham failing to trust God to protect him. Despite God's repeated promise to give him a son by Sarah, Abraham worries that she will be taken from him and that he will be killed. He falls back on his old trick of lying about her being his wife. This isn't surprising. The truly amazing part is that God remains faithful to him. God intends to keep His promise - so much so that he prevents Abimelek from being able to perform sexually, thus preventing any doubt over whose child Sarah will carry. He continues to acknowledge Abraham when his behaviour is so embarrassing. What a poor witness Abraham is, what a faithless man. Abimelek - the pagan - is more upright, honest and God-fearing than Abraham at this point. And yet, God still calls Abraham a prophet, still protects him and still listens to his prayers. Then Abraham prayed to God, and God healed Abimelek, his wife and his female slaves so they could have children again. (Genesis 20:17)
What we learn here is that it is God's faithfulness that saves us, not our own. We see God's grace at work in Abraham's life. This believer stumbles, but he is secure in God's promise. Our failures do not cause God to desert us.
This is the eternal security of the believer. Once saved, we are saved for good, even when our behaviour doesn't live up to that. This is Grace.