How has Abraham's covenant promise been fulfilled over the last 4,000 years?
Over the past 4,000 years, Abraham's covenant promise of numerous offspring has been fulfilled through the line of Isaac and Jacob, forming the nation of Israel. Though Israel has often been a small nation, tremendous numbers of people have descended from Abraham according to that promise. God also gave a further promise in Genesis 15 tying Abraham to us.
Les explains that in Genesis 13:16 God enlarges the covenant promise, saying Abraham's seed would be as the dust of the earth. This meant a great offspring through the line of Isaac and Jacob, or the nation of Israel. Over 4,000 years, even though they have been a small nation, tremendous numbers of people have come out of this covenant promise. Then in Genesis 15:5 God does something totally different: He gives Abraham a promise that ties him to us. Les also notes that God dealt with Abraham face to face, possibly taking on human form, as at the calling out of Ur, where Acts 7 uses the word optomai for the Lord appearing to Abram.