Union with Christ seems to be the paper that the gospel is written on. Whatever aspect of the gospel and salvation you are looking at, union with Christ is there. Sinclair Ferguson’s The Christian Life has some excellent thoughts on this topic. Though having a chapter on union with Christ, union tends to be a thread woven throughout the whole book. Consider the following:
In Christ. It is in Christ we receive all the blessings of the Christian life. We are chosen in him. In him we are predestined to be like him. In Christ we are called, and in him born again to newness of life (1 Pet 1.3). In him we have faith, and receive the Holy Spirit. In him we are brought into the privileges of brotherhood in the family of God. In Christ is our sanctification (1 Cor 1.30). When we see him, we will be made like him, for when he appears in glory, we shall also appear with Christ (1 Jn 3.2; Col 3.4). From beginning to end all blessings are ours in Christ.
It is interesting that Fersuson (and the bible) don’t talk about getting things ‘from Christ’, but getting things ‘in Christ’. That is a massive and significant difference. How often do we hear about getting things from Jesus, as opposed to having Jesus himself, and all of these other things in him.
What is the result of all of this? Well, Ferguson goes on to mention it should produce a deeper humility, steadier assurance, and lead us to worship. A few more words on a steadier assurance:
Lack of assurance is often caused, like a sense of inferiority, by being too taken up with ourselves. But our assurance does not lie in what we are, be we great or small. It lies in what God has done in his plan of salvation to secure us to himself. ‘Believe God’s word and power more than you believe you own feelings and experiences’, wrote Samuel Rutherford to a correspondent. ‘Your Rock is Christ, and it is not the Rock which ebbs and flows, but your sea’. The more we know the strength of our Rock, and understand that we have all the blessings of the Christian life secure in him, the more steadily assured we will be and the greater will be our joy.