The expression “in Christ” sums up as briefly and as profoundly as possible the inexhaustible significance of man’s redemption. It speaks of security in Him who has Himself borne in His own body the judgment of God against our sin; it speaks of acceptance in Him with whom alone God is well pleased; it speaks of assurance for the future in Him who is the Resurrection and the Life; it speaks of the inheritance of glory in Him who, as the only-begotten Son, is the sole heir of God; it speaks of participation in the divine nature in Him who is the everlasting Word; it speaks of knowing the truth, and being free in that truth, in Him who Himself is the Truth. All this, and very much more than can ever be expressed in human language, is meant by being in Christ.
Philip Hughes