On closer examination of the texts we find that a pattern clearly emerges. There is no mention of being baptised together [discussing Galatians 3:25-27], but only of being raised together and seated together. The fulcrum for this change from an individualistic to a corporate dimension is clearly the event of the death of Christ. The believer is baptised into His death, as an individual, and consequently raised, together with all other believers, to share in the blessings of the eschatological community. The question that must be posed is when did this baptism take place and what was the nature of it?
It is very important to realise that if these texts refer to water baptism, then it means that before the believer’s oneness with Christ was established, believers were seated in the heavenlies (Eph. 2:6). Hodge was aware of the need to emphasise that the raising up of the believer with Christ is an historic fact, that believers were actually raised with Christ when he came out of his grave. What Hodge, nor any other commentator to my knowledge do not ask is how could this actual historical exaltation take place without any prior union. In other words, the logic of Paul’s thinking requires that the unity is established long before water baptism is administered, even before the experience of conversion and the reception of the Spirit. Indeed, if the believer (or better the church, for the language Paul uses of being raised is corporate) was raised with him, then the unity had to be in existence even before Christ left the tomb. . . .
This time scale problem is overcome once it is realised that alongside the baptism into Christ is the type of the baptism of the Israelites into Moses in their Exodus. All Jews, according to Gamaliel the second, of all preceding and subsequent generations were present in the coming out, and shared in the baptism that made Moses their leader. It was then that Israel became the Son of God and Spirit was given her to lead her through her wilderness journey.
This explains why Paul has been so decisive in his use of the preposition syn. There is no unity of believers, neither with each other nor with Christ, until they have been united together through baptism. Paul has been careful to define this baptism in terms of its occasion, for it was a baptism into Christ’s death. As Moses, in the Exodus out of Egypt, took the people of God, for they were united with him through baptism, so Christ takes those who have been baptised into union with him from the realm of sin and death. This baptism into Christ took place in his exodus, in his coming out of the realm of Sin and death. It was a baptism into his death that all believers experienced, in the same historic moment.
There was no union either with each other or with Christ until it had been created by the Spirit. It was this baptism that brought the covenant community into existence. Therefore if one asks when did the church historically come into existence, the answer is at the moment of Christ’s death, for it was then that the Spirit baptised all members of the covenant community into union with their Lord and Saviour. Once this union had been established, Paul was free to use the preposition ‘en (in) which speaks of the fellowship of believers in Christ. From then on, in terms of ultimate reality, no believer could experience anything apart from all other believers, for their union with Christ is such that all other believers are also partakers in Christ’s saving work.
What I am arguing for is that the baptism passages which we have considered are speaking neither about water baptism nor even of Christ’s baptism into his sufferings, even though these are important related themes, but about a baptism modelled on the baptism of Israel into Moses when Israel came into a covenant relationship with Yahweh through the representative He had appointed. In Romans 6 (and in 1 Cor 12:13; Gal 3.:5ff ; Eph 4:6 and 5:25f) Paul is demonstrating how the old order has been brought to an end and how the new eschatological order has come into existence. It is because believers have shared in the death of Christ, with the consequence that they have died to all the covenantal demands of the old relationship that bound them mercilessly to Sin and Death (Satan), that they are now free to live lives unto God who has made them his own through Christ his Son.
Holland, Tom. Contours of Pauline Theology. London, UK: Christian Focus Publications, 2004. 150, 151-52.