Judges 1:2 & 3
The Lord answered, Judah shall go up; I have given the land into their hands.' The men of Judah then said to the Simeonites their fellow Israelites, 'Come up with us into the territory allotted to us, to fight against the Canaanites, We in turn will go with you into yours.' So the Simeonites went with them.
When they inquired of the Lord, the answer was that Judah was to go forth and that God had already given them the victory. Instead of believing that and trusting in the Lord, they went to their fellow Israelites for help. Although this may sound like a good thing, it was not because they did not trust in God. As Christians, we often do the same type of thing as we seek the counsel of men instead of acting on the word that God has already given to us. If we are in Christ, then, He has already given us the victory and the ability to dwell in this world with Him as our guide. Our fellowship with other Christians is a good thing to build us up and to encourage us but it is through the strength of God that we can glorify Him in our walk.