“the church of the Thessalonians which is in God the Father and in the Lord Jesus Christ:”
This is the smallest, yet might be the most important word in verse 1. “In”.
Every true church is in.
Which Implies vital union.
God has their life and their loyalty and is their goal and their aim.
They were spiritually “out”, now they are “in”.
How? What happened?
(en theōi patri kai kuriōi Jēsou Christōi)
By grace, through faith, they are in Christ.
This is the Gospel.
“I am no longer my own, I have been made new.”
How many times have you tried to share the Gospel with someone who fends you off with “I’m a Christian”.
No, you may have a Judeo-Christian ethic.
You may have a vague notion of “there being more to this”.
But the mark of the believer is that you are in God the Father, you are in Christ Jesus, you are in.
Not what you do, not what you don’t do.
But where you are. Metaphysically. In.
Many are near.
Many are on the outside, on the periphery.
They’re looking in, but they’re not.