Baptized Heirs with Abraham (Gal. 3:27)

Many people in the church today think that baptism is merely a New Testament symbol demonstrating that the church is different from Israel. However, the Apostle Paul does not see such a distinction in the people of God. Is the church the replacement for Israel? Is the church something that is radically different from Israel? What does the sacrament of baptism have to do with Israel and the church?