Satan, the god of this world, blinds the minds of the lost, preventing them from believing the gospel.

"But if our gospel be hid, it is hid to them that are lost: In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them." - 2 Corinthians 4:3-4

If we want souls to believe and obey the gospel so that they can be saved, we must take up the weapons of warfare against the devil, the god of this world.

"For though we walk in the flesh, we do not war after the flesh: (for the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;) casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;" - 2 Corinthians 10:3-5

In order to participate in spiritual warfare we must be prepared by obeying the gospel ourselves – we must repent, be baptized in Jesus name for the remission of our sins, and receive the gift of the Holy Ghost. (Acts 2:38)

We must take a stand for truth and righteousness, and walk by faith. The Word of God is our sword, so we need to be familiar with it so we can use it skillfully, as Jesus did when the devil came to him in the wilderness (Matthew 4:1-11)

Our weapons include prayer. We are to pray in the Spirit. We must pray for souls to be saved and pray for those that are ministering to souls. Travailing prayer births souls into the kingdom of God. (Ephesians 6 10-20, Galatians 4:19, Psalms 126:5-6)

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost." - Acts 2:38