2 Cor. 5:17, Therefore if anyone is in Christ, he is a new creature; the old things passed away; behold, new things have come.
Think of the Iron Man super hero as an example of being in Christ. When Tony Stark is enclosed by the Iron Man suit he becomes a different person in The Suit. You could say he, while in the suit, is in Iron Man, and because he has a artificial heart that is connected to the functioning of the suit we could say that Iron Man is in him. As long as he is in The Iron Man suit he is able to see and do amazing things, and because of that, the way he thinks is totally different while in the suit. In Iron Man he thinks, feels, speaks, and acts from Iron Man. Outside of the suit, he is only Tony Stark, living with all of the limitations of his humanity, but in Iron Man he is capable of everything Iron Man can do. He is still Tony Stark, but much more. His identity, ability, and destiny in the suit is completely different.
I’m sure this is a very weak example, but it does give you some idea of what it means to be in Christ. According to that verse above, we have all become new creations in Christ. It’s because we’ve been placed in him that we are new creations. Don’t think of that in some strange dead theological sense, but think of it in light of your dynamic union with Christ. You and I have been placed into his life, and because we’ve been placed into his life that he also now dwells in us. It is a mutual indwelling. You don’t become a new creation because he somehow touches you and makes you a new creation; instead you become a new creation, with a new identity, ability, and destiny, because you’ve been placed into his very life, and you and I get to live in and from that reality and perspective. His ability is now your ability. That’s why the word of God calls us to abide in Christ. If you are a Christian then you are in Christ, but we are called to abide, that is, dwell consciously, and intentionally in that reality. Only as you live aware that you are in Christ, and you think, speak, and behave from that truth, do you get to enjoy the supernatural experience of being a new creation in Christ. How sad it would be for Tony Stark to be in the Iron Man suit and yet try to handle every situation that came his way as if he were simply Tony Stark with all the limitations of his humanity. Imagine what one day would be like in your life if you could clothe yourself in Christ, or is it Christ clothing Himself with you. Remarkably it is both and. Think of what kind of day that would be.