2 Corinthians 10:3-5 (Darby)
3 For walking in flesh, we do not war according to flesh.
4 For the arms of our warfare [are] not fleshly, but powerful according to God to [the] overthrow of strongholds;
5 overthrowing reasonings and every high thing that lifts itself up against the knowledge of God, and leading captive every thought into the obedience of the Christ;

The word stronghold in the seventeen contexts used in the Bible means stubbornness or rebellion. It is the refusal to heed instruction or advice.
What are strongholds? A stronghold is a strongly fortified defensive structure, arguments or pretension that sets itself up against the knowledge of God, and anything that exalts itself in our minds pretending to be bigger or more powerful than God.
Whether the stronghold is a superstitious belief, an addiction, wrong thoughts, and despair over a loss, etc. – if it is something that consumes our emotional and mental strength, then it’s a stronghold. A stronghold is something that people depend on for safety, assurance and comfort, whatever you feed will gain mastery over your mind, spirit and body, see Colossians 2:8.
Spiritual strongholds are the arguments and pretensions that people use against the knowledge of God. Skilful use of the sword of the Spirit will demolish these strongholds, making them ineffective.
The world wages war with physical weaponry: planes, ships, tanks, guns, and bombs. But they have no value in the spiritual conflict we are a part of. Instead, we have spiritual weapons that have the power to demolish every stronghold.
We are all armed with spiritual weapons and strategic strength for warfare that will successfully demolish spiritual and physical strongholds fortified by the work of Christ and empowered by the Holy Spirit according to Ephesians 6:13.
Christians must be sure that their measuring stick for every prophesy and decree they claim is from the revelation of the scriptures rather than against the spiritual truth of human reasons and to cast down any teachings against the knowledge of God. We cannot have a positive life with a negative mind that’s why we must take negative thoughts captive, it’s not easy though, but according to Romans 12:2, it can be done through the word of God.
The lies of the enemy are vicious and destructive. Strongholds try to invade our minds every day, and it takes commitment and discipline to control the mind.
The enemy schemes to kill, steal and destroy the children of God, we all need to be aware of these schemes in whatever form they come. Satan’s schemes are devious tactics used in every way to gain spiritual ground over us according to 2 Corinthians 2:11 and John 101:10.
So many things are contending with the knowledge of God in our lives, homes, families, communities, and nations right now, contending with the power of God but by scripture’s command and assurance, we can cast them down.
Anything can be a stronghold, our societies and nations of the world are experiencing such violence, hatred, greed, and more that have become strongholds: the stronghold of brutality, race, witchcraft, lust, lies and death have become the norm rather than the exceptions.
The Lord has given us authority and command to destroy the agenda of wickedness, and darkness holding us captive, we have been authorized to break off every stronghold in Jesus’ name. according to Matthew 18:18, we have the authority to cancel, cast down and destroy every legal ground giving the enemy strongholds in our lives.
Do not give the enemy foothold, because he’ll end up taking a stronghold that will cripple your work and walk with the Lord. Demolish those strongholds by the power of the Holy Ghost.
Shalom