Deuteronomy 20 gives the rules for going to war.  Verses 3-4 " ... Do not be fainthearted. do not be afraid, or panic, or tremble before them, for the Lord your God is the one who goes with you, to fight for you against your enemies, to save you. "
Any person who is afraid, or who has a need to stay at home, was given an opportunity to stay behind and not enter into the battle.  God is strong enough to fight the battle without them.

We forget that.  We forget that it is God who fights our battles too.  He has conquered the enemy thoroughly.  We do not need to fear or panic or faint... or be depressed.. or give up.  We need to stay strong by going out in faith... or staying home in faith.   God is for us!  He cannot fail.  He will not leave us or forsake us... even if we are afraid.

Father in Heaven,  You are mighty and awesome and full of grace and mercy!  You love us and have called us to be Your sons and daughters.  You will fight for us.  May we not forget.  May be truly believe!  Thank You for the heavenly armor that is ours in Christ Jesus - the belt of truth; the breastplate of righteousness; the helmet of salvation; the shoes of peace, the shield of faith and the sword of Your Spirit.  In Christ we can stand and keep on standing.  Help us to remember that our struggles are not with flesh and blood but with the spiritual forces of wickedness and we can only stand against that with Your help, praying constantly.   Make us strong in the Lord and in the strength of Your might.  In Jesus's Name, amen.