Given that the Word and sacraments are the means of grace in the New Testament period, was there an equivalent for the Old Testament period? How do circumcision and the Passover relate to this? Also, if Paul in Galatians describes circumcision as a work of the law, and condemns adding it to faith, how does he also directly tie circumcision to baptism in Romans? If Paul consistently presents baptism as gospel, why does he tie it to the Old Testament work of circumcision? Or was circumcision a work at all, or was that the view the Jews had taken on at the time? And I've recently found the idea of God's presence confusing. In the Old Testament, God's presence could be found in the Most Holy Place, which was accessed once per year by the High Priest. Does this mean God wasn't present in His Word throughout the Old Testament, at least when it had been recorded and written for the people? And no doubt Old Testament believers are saved the same as we are, through faith alone. All their sins were pardoned by Christ. If this is true, how does the idea of God's presence shift from the Old Testament to the New Testament? And lastly, from my understanding, there's seems to be a distinction between God's more general presence (omnipresence) and His special presence in the means of grace. Is this a correct way of thinking about His presence? Thank you for all the help!
God the Holy Spirit has always used the Word of God to bring people to saving faith in Jesus Christ, the promised Messiah (Romans 10:17). For the male population of God’s Old Testament people of Israel, circumcision was a seal of the righteousness that was theirs by God-given faith in the promised Messiah (Romans 4:11).
As the rite of circumcision no longer applies to followers of God in New Testament times, the apostle Paul rightly condemned the requirement to be circumcised, along with believing in Jesus Christ as Savior, to enjoy salvation. The book of Galatians addresses this.
What that same apostle did in another inspired letter was to speak of a parallel between circumcision and Baptism: “ In him you were also circumcised with a circumcision not performed by human hands. Your whole self ruled by the flesh was put off when you were circumcised by Christ, having been buried with him in baptism, in which you were also raised with him through your faith in the working of God, who raised him from the dead” (Colossians 2:11-12).
The original Passover gave the Israelites deliverance from their enemies. The ongoing Passover observance pointed ahead to the perfect Lamb of God, Jesus, who would take away the sins of the world (John 1:29).
When it comes to the presence of God, the Bible teaches that God has many different modes of presence. He is omnipresent (Jeremiah 23:24; Psalm 139:7-10). He is present in the Lord’s Supper, as we receive the Lord’s body and blood, together with the bread and wine (1 Corinthians 10:16; 1 Corinthians 11:27). He is present with his church—when two or three come together in his name, as you referenced. He is present with each believer, as our body is a temple of the Holy Spirit (1 Corinthians 6:19). He is present with each believer because he lives in them (John 17:20-23). Jesus was visibly present among people when he came to this world as true man (1 John 1:1-2).
Your numerous questions could certainly receive fuller treatment, but this is about the best I could do with limited response space.