If I want to grow watermelons in Tennessee today, I do not have to have an unbroken watermelon vine stretching down through all the millennia from the Garden of Eden to Tennessee. All I have to do is plant watermelon seeds in Tennessee today. They will produce in Tennessee today what they have always produced—watermelons!
Similarly, to have the undenominational church of the New Testament in the 21st century, we do not need an unbroken line of faithful congregations stretching down through all the centuries from the Day of Pentecost to the present. All we have to do is to plant the seed (the word of God, Luke 8:11). It will produce in the 21st century what it produced in the first century—undenominational congregations (churches) of the Lord!