Children of Abraham

"The promise comes by trust, so that it may be by grace and may be guarenteed to all Abraham's offspring- not only to those who are of the law but also to those who are of the faith of Abraham. He is the father of us all. As it is written: 'I have made you a father of many nations." He is our father in the sight of God, in whom he believed-the God who gives life to the dead and calls things that were not as though they were" (Romans 4:16,17) Can we, who are saved by faith in Jesus and belief in His dying on the cross for are sins, be any less trusting than Father Abraham?