I will strengthen your inner being by the power of My Spirit.

Ephesians 3:16 

that he would grant you, according to the riches of his glory,
that you may be strengthened with power through his Spirit in the inward man;

In today's promise, the Apostle Paul is praying that our God and Father would strengthen our inner being by the power of His Spirit. We all need supernatural strength to flow from our spirit and it is important for us to know that the source of that strength comes from God alone. In Zechariah 4:6 the Lord says... ‘Not by might nor by power, but by my Spirit,’ says the LORD Almighty. (NIV)

I like how the Amplified Bible translates Ephesians 3:16...May He grant you out of the rich treasury of His glory to be strengthened and reinforced with mighty power in the inner man by the [Holy] Spirit [Himself indwelling your innermost being and personality]. (AMP)

The strength that we need today comes from only one place...Out of the rich treasury of the glory of God that flows directly from God's own Spirit to our spirit. So look to God for your strength and not to your own resources.

It is not by our own self effort or personal goodness that we will have power to live a godly life, but through the free gift of the Holy Spirit that God has already given us as a deposit to guarantee our inheritance (2 Corinthians 1:22)