'In Christ' in the Bible

The end [i.e., of being so predetermined] was that we [Jewish Christians], who had previously placed our hope in Christ, should bring about the praise of God's splendor.

You [Gentiles] also, who are in Christ, after having heard the message of truth, the good news about your salvation, and [after] believing in Him, were sealed [i.e., as evidence of ownership] with the promised Holy Spirit. [or, "the Holy Spirit who brings promises"].

and be kind and compassionate toward one another, forgiving each other, just as God also forgave you [because of your fellowship] in Christ.