For Joshua and the people to advance there was a clear initial military objective to be achieved: overcome the fortified city of Jericho. For any advancing people it was a blocker. But God gives clear instructions via an angel-warrior - that this would not be by a single spear, boulder thrown, or battering ram.
Instead it would involve walking around, with the ark (representing the presence of God among them), some trumpets, and a shout. This is because it is a spiritual exercise, because it is a spiritual battle. We must remember that we too are in a spiritual battle. 2 Corinthians 10 reminds us that we live in the world but do not wage war as the world, we fight with spiritual weapons with divine power to demolish strongholds.
To sum this up: we are not against people but rather we are for people; we name or call-out ideologies that are problematic; and we come against spiritual forces.
Back in the story they were to march round Jericho for seven days. On the seventh day there were to march seven times. The number seven is familiar to us! It echoes the creation story, so each circuit reminds and declares (without any military strength) that God is God, that He created the world, He is in control with all authority. Of course the creation story leads to the seventh day in which God rested - symbolic of God taking creation to His intended perfection. The 'shout' in the story (a praise shout) is therefore a culmination and overwhelming declaration of God and all things belonging to Him. In view of His ultimate perfection any resistance, any evil, anything that would try and stand in the way of God must come down. It simply cannot stand any longer. It goes!
Recall previously we drew parallels between Old Testament Israel and the New Testament people of God (the church). When Jesus talked of the church he said 'I will build my church and the gates of Hades (death or hell) will not prevail against it'. In short this is the people of God versus strongholds of the death/devil. The strongholds will not win out against the people! Commentators argue about the verse, but my own pondering turns up verses like Psalm 107 verse 16 which talks of breaking gates of bronze, cutting bars of iron. So 'gates' seems to convey a general sense of 'strength'. I conclude that such strength of death or evil won't stand against the church, and strongholds that keep people locked up or prisoners can be taken down.
On a practical level this means we can pray directly and boldly. Lets drop the namby pamby approach with the ifs and buts! First lets get out of the habit of saying 'Lord I just pray ...'. We are not just praying, we approach with boldness as a son or daughter of the King! For sure we remain humble (we are dust, He is God) - Joshua in front of the angel bowed to the ground, had to take off his sandals. Yet that doesn't mean we cannot ask with confidence.
Second we can learn to subtly switch within prayer to addressing evil: we can declare that malign spiritual activity must go. This is akin to 'addressing the condition' when we pray for healing. Yet note we do this based on discernment while praying, especially paying attention to the specific case, person or condition. Mistakes people make are to give the devil a focus, or see an evil spirit under every bed or around every corner. This can lead us to picking a fight that just isn't there or we are not called to. As with our advice to parents of teenagers: pick your battles!
Having said this, however, we know in general there are malign spiritual forces, keeping people captive, blinding eyes - so there is a sense we can come against these without specific discernment.
Yet we should be clear that when we pray in this way, that strange random things are likely to happen. In our recent week of prayer we deliberately prayed with a sense of being 'on the offensive'. In the following days random things broke! Each single thing is just a nuisance, but cumulatively they build up. We have learnt to understand this as 'spiritual attack', and learnt to respond by simply re-declaring our grounding in God - He is God and we can be assured in Him. Everything we do, we do within His armour - it is about Him, not our cleverness or strength. So we can venture forward without fear, rooted in Him, knowing it is His battle. He has done enough on the cross.
Jericho the stronghold was a blocker - but the walls came down. What are the blockers for us, or for the people we see or that we are trying to help? Let us learn to express that spiritually: not 'person X hurts me', but sensing the underlying spiritual dynamics that are at play (e.g. lack of forgiveness, or a lack of understanding). These dynamics we can pray into, and with discernment can boldly pray against.