God’s blessing on Abraham spills over into the lives of Abraham’s family members: his wife (barren/bearing son), his two sons (Ishmael - prince over 12 tribes / Isaac the father of Israel, the lineage of Messiah), and all their offspring. 

The blessings of God in our lives can spill over into the lives of our family members (and others).  They are designed to do so, but you have to obey God and walk before God blamelessly in order to get the blessing.