In this way, within covenant theology, “Israel-church” are so linked that it becomes hard not to say that the only major difference between the old and new covenant people of God is that the New Testament “church” is a racially mixed and non-national Israel, and that the “church” is a more knowledgeable version of the old covenant people of God. But the work of the Spirit in terms of regeneration, indwelling, and sealing is basically the same across redemptive-history.
– Stephen Wellum, Kingdom Through Covenant, 58-59.