At the end of Joshua 5, the people have successfully entered the land they were promised and are poised to take Jerhico. Joshua is out doing something (the text doesn't really say what) at the end of chapter 5. verse 13-15 and we read (New Living Translation):
When Joshua was near the town of Jericho, he looked up and saw a man standing in front of him with sword in hand. Joshua went up to him and demanded, “Are you friend or foe?”
“Neither one,” he replied. “I am the commander of the Lord’s army.”
At this, Joshua fell with his face to the ground in reverence. “I am at your command,” Joshua said. “What do you want your servant to do?”
The commander of the Lord’s army replied, “Take off your sandals, for the place where you are standing is holy.” And Joshua did as he was told.
Here is Joshua and Israel about ready to follow orders that are strange, marching around a city to conquer it, and we find out that God's army is not on Israel's side but on Gods.
Why did that catch my attention? Because way too often we find a righteous cause and assume that because it is what we think God would approve of (or even has told us to do) that he is on our side.
The choice as I see it is not whether God is on our side but are we on Gods?