In almost the same breath God spoke and said, "I will fight your battles for you." Paul says in II Corinthians 10:4, "For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds." So if we follow the principles that God laid down, we will maintain a good spirit.
The Lord spoke unto Jehoshaphat, "Ye shall not need to fight in this battle" (II Chron. 20:17a). The Lord fought for them. They only had to worship God. If there is any fighting to do, let the Lord do it. This does not mean that we are not to contend for the faith or that we are to recant, but it means that without God we are not able to do anything.
The great battles waged in the Church many times by carnal expediency has only brought division. Our battle is fought by the Spirit of God. "Not by might, nor by power, but by my spirit, saith the Lord of hosts" (Zech. 4:6).