Ephesians 6:10

In conclusion, be strong in the Lord (draw your strength from Him and be empowered through your union with Him) and in the power of His (boundless) might. 

Our strength comes from the Lord and His word. We are to speak our authority and bind, cast down, and stand against all the devices that Satan sends our way. Hold fast to our confession of faith and speak the truth in love, keeping our minds renewed in the Word.