TBe sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour. - 1 Peter 5:8
Taking Authority means not allowing the devil to prosecute or persecute you for your past sins. The devil and his beasts of the field and his workers of iniquity, etc., will continue to hold you captive for what you have done wrong no matter how long ago it was, no matter whether you have repented, asked for forgiveness, no matter what.
Taking Authority means you don't allow the devil to continually hold you a prisoner or incarcerate you for your sins especially when God has set you free. Even if you are in the mess you are in at no one's fault but your own, you still can take authority over the devil and take back our power and not let him control or dominate you anymore.
We take authority over the devil by paying attention to the devil's tactics, plots and schemes and not allowing the devil to gain access to our minds or our hearts. The devil is the grandfather of lies and everything that comes out of his mouth is false.
Taking authority means we become steadfast in our commitment to stay alert, and on guard making sure the devil doesn't successfully sneak up on us or engulf or overtake us. Be on guard and watchful at all times and be on the lookout to make certain no enemy nor aggressor can successfully gain entry into our hearts, minds or lives.