While Israel and the Church are distinct and unique creations by God, it must also be remembered that there was a time when neither existed. Jesus' death, his payment for sin, provided for all mankind. This includes all who believed in YHVH before either Israel or the Church existed. The death of Christ was the watershed event in human and divine history. In God's plan, it was the events towards which all history was working.
Nothing is the same since that event.
In military terms, the death and resurrection of Christ was the strategic victory of God in his campaign against sin, death, and evil. Now that the strategic victory has been won, we are involved in various tactical phases of the war. God is presently taking out a people for himself as a bride for Christ. This is the Church. After this effort is fulfilled, he will pour out his wrath upon the earth and save a repentant Israel.