'In Christ' in the Bible
To the saints and faithful brethren in Christ which are at Colosse: Grace be unto you, and peace, from God our Father and the Lord Jesus Christ.
Since we heard of your faith in Christ Jesus, and of the love which ye have to all the saints,
For God was very pleased to have all of [His] fullness dwell in Christ [See 2:9],
[And this He will do] provided that you continue to stay with and in the faith [in Christ], well-grounded and settled and steadfast, not shifting or moving away from the hope [which rests on and is inspired by] the glad tidings (the Gospel), which you heard and which has been preached [as being designed for and offered without restrictions] to every person under heaven, and of which [Gospel] I, Paul, became a minister.
Now I rejoice in my sufferings for you, and I am completing in my flesh what is lacking in Christ's afflictions for His body, that is, the church.
Whom we preach, warning every man, and teaching every man in all wisdom; that we may present every man perfect in Christ Jesus:
For though I be absent in the flesh, yet am I with you in the spirit, joying and beholding your order, and the stedfastness of your faith in Christ.
For it is in Christ that the fulness of God's nature dwells embodied, and in Him you are made complete,
And you are in Him, made full and having come to fullness of life [in Christ you too are filled with the Godhead -- "Father, Son and Holy Spirit -- "and reach full spiritual stature]. And He is the Head of all rule and authority [of every angelic principality and power].
In whom also ye are circumcised with circumcision made without hands, by putting off the sinful body of the flesh, through the circumcision that is in Christ,
and having divested principalitys and powers, he made them an example of obedience, and caus'd them to triumph in Christ.
These things are [only] a shadow of future things, but the body [i.e., the real substance of things] belongs to Christ. [Note: The idea here is that the ritual observances of the Mosaic law were like shadows pointing to the reality of life in Christ].
Children, always obey your parents, for that is commendable in Christians.