Let me ask a couple of questions. I think I know what SFIC was getting at when he refers to Exodus 20 as not relating to Christ but to God the Father. He is not saying that only the Father is to be worshiped and Christ is not coequal with God but that God is dealing with Israel personally. That Christ is worshiped as God but not here as the Son. While I do not know much about modalism it seems to me that even it seeks to explain the Holy Trinity an existence that is hard for the human brain to comprehend. I personally think that God worked in three distinct ways as He dictated in each age. First He guided his children (sons of God) as they were removed from the garden to the flood. Then He picks up with Abram and develops his faith through testing and wanderings. This continues through the Law and the Prophets. While God is directly leading them Christ is indeed present. The Ark is safety in Christ above God's wrath, the flood. The pillar of fire and smoke guiding His children by day and by night through the wilderness, is the Holy Spirit. The cleft of the rock that kept Moses safe, as God passed by, was Christ. The Rock that Moses struck was Christ. The tree that made bitter waters sweet was the cross. So we have God the Father, God the Son and God the Holy Spirit are indeed working at the same time. They are working in unison as one God. The same is done in the New Testament. Is this Modalism? If so, how is it heresy? And who are we that we can judge what is heresy? It seems to me that heresy is the complete denial of the salvation work of the death, burial and resurrection of Christ. How then is it heresy to worship God as one God triune?