Ephesians 3 Verses 1-13 "For this reason..." Paul begins,  Because both Jews and Gentiles have been united together in one building, one holy temple that is the "dwelling of God in the Spirit" -  Paul was made a steward of the grace of God for the Gentiles.  What had once been a mystery, a secret, hidden plan, was revealed now.  " ... to be specific, that the Gentiles are fellow heirs and fellow members of the body and fellow partakers of the promise in Christ Jesus through the gospel."

Paul's ministry was a "gift of God's grace".  Grace that was the "working of His power."
Grace  "to preach to the Gentiles the unfathomable riches of Christ."
Grace to "bring to light what".. was "hidden in God who created all things"
This was God's plan, according to His "manifold wisdom" and His "eternal purposes".

God's great wisdom and grace had planned and purposed since before the creation to bring all things together in Christ Jesus our Lord.

Verses 14-21 Paul prays, beginning with the same three words, "For this reason".  Because of  God's great plan,  " I bow my knees before the Father,"...
We worship our God Who has righteously and lovingly granted salvation to all who believe in Jesus Christ the Lord.  No matter what family, or tribe, or nation,  all who call upon the Name of the Lord will be saved.
Paul prays for these believers and we can pray these same things for ourselves and for others, praying that:
"He would grant you, according to the riches of His glory, to be strengthened with power through His Spirit in the inner man."  Notice this is something God grants, that He has the resources to grant it, and that He Himself does it in the Person of the Holy Spirit, and that He does it inside of us. 

"So that"... We must have what we are asking for, we must have His Spirit giving us His power, to strenghten us inside..  in order that:
1.  " Christ may dwell in (our) hearts through faith;"   and that,
2.. We " being rooted and grounded in love may be able to comprehend the love of Christ which surpasses knowledge,"  and
3. "That (we) may be filled up to all the fullness of God." 

One request with 3 amazing results! When we ask God to grant us this spiritual strength by His Spirit power - Christ abides in our inner self, through faith; we grow into and are built into Christ's love.. we can know the unknowable love of Jesus; and we are completely filled with all of God.

"Now to Him who is able to do exceedingly abundantly beyond what we ask or think, according to the power that works within us, to Him be the glory int the church and in Christ Jesus to all generations forever and ever. Amen."