Ephesians 6:10
Finally, be strong in the Lord and in his mighty power.
‘the power of his might’ is a Hebraism (a popular Hebrew saying)
‘strong and mighty’ Psalm 24:8
‘most mighty’ ‘almighty’ = God’s infinite almighty power
To be strong in the power of the Lord’s might implies two acts of faith;
1. a settled firm persuasion that the Lord is almighty on power – strengthen and entrench yourself in this. Is this your firm conviction? are you fully persuaded?
2. Not only must we believe that God is almighty, but also strongly by faith we rest on this almighty power, as engaged for our help and aid in all our trials and temptations.
Psalm 138:3 AMP
3 In the day when I called, You answered me; and You strengthened me with strength (might and inflexibility to temptation) in my inner self.
Paul discourages the Christian from resting on his/her own strength. We are to lean on the arm of the Almighty, as it were our own strength. He is encouraging the Christian to make use of God’s almighty power, as freely as it were his own whenever assaulted by Satan in any kind of trial and temptation.