On how God is to be worshipped today.
"God [is] a spirit; and they who worship him must worship [him] in spirit and truth" (John 4: 24).
Three Musts - on why worship must be in spirit and in truth
Two Veils Not One - the veil of the temple and the veil of the tabernacle and our approach to God
We Call on Him - on how the Old Testament practice of calling on the name of Jehovah is continued in Christianity by calling on the name of the Lord Jesus