Ephesians 1:3, 4 (NASB)
Blessed be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in the heavenly places in Christ, just as He (God) chose us in Him (Christ) before the foundation of the world, that we would be holy and blameless before Him.
As discussed in the previous post, the phrase "in Christ", refers to our union with Christ. A way of reading to understand this section may be "God Blesses Our Spirit Because of Our Relation to (or Union with) Christ."
A breakdown of Ephesians 1:3 looks like this:
“Let us praise God, who is the God of our Lord Jesus and also his Father. For as we are united with Christ, God has blessed us by giving us every spiritual blessing in the heavenly world.”
Then verse four:
“God had already chosen us to belong to him by means of our being united with Christ, as God would want us to be.”
The way God wants us to be is holy, pure, blameless, clean....to break it down simply, it is without sin!
When we are in union with Christ, our life is lived in His sight and His presence! We are open to His scrutiny.
Reference:
Bratcher, R. G., & Nida, E. A. (1993). A handbook on Paul’s letter to the Ephesians. UBS Handbook Series (pp. 8–13). New York: United Bible Societies.