And the Lord said to Joshua: "See! I have given Jericho into your hand..." —Joshua 6: 2
If you want victory over the strongholds of the old nature, look at Israel's conquest of the land. The principles of victory are found right here. First of all, notice that God spoke to Joshua in the past tense. "I have done it. It is finished." In the same way, your victory is a finished work of Jesus Christ. The Lord has already provided you with victory over your flesh life— all you have to do is believe it.
The second principle is to follow God's plan for victory even when we don't understand it. God's plan for conquering Jericho was interesting, to say the least. As Joshua called his generals together to explain the battle strategy of marching around the city, they probably began to have second thoughts about their allegiance to follow this guy.
God's plan for your situation may seem peculiar. And you may even be reluctant to try it. Obey the impressions of God upon your heart.
The third principle is that the people were to give a great shout of victory— even though the walls were still standing. This was an expression of faith and anticipation.
We can trust God's Word. He promises that He is going to work. Praise Him for those promises of victory. God doesn't want you to go on in defeat, being mastered by your flesh and the strongholds of the flesh-life. Turn your life over to Him and trust Him. He will bring the walls down.
Father, thank You for the glorious victory that we can experience through the power of Jesus Christ. Thank You for setting us free from our past sins.