2 Chronicles 20:12 & 15 b
O our God, wilt thou not judge them? for we have no might against this great company that cometh against us; neither know we what to do: but our eyes are upon thee.
Thus saith the LORD unto you, Be not afraid nor dismayed by reason of this great multitude; for the battle is not yours, but God's.
There will be times in our lives when we feel we are in a great battle. It may be a physcial battle (finances, health, etc.) or a spiritual battle (faith, depression, etc.). In either case, we need to remember that God is with us. We need to admit that we don't have the power to succeed, but we know the one who does--God--and we need to keep our eyes on Him and allow Him to do His work.
He will tell us not to worry because He is in control. It isn't a fight we need to fight. The fight belongs to Him.
So, when you feel you are up against a great multitude, keep focused on God and step back and follow His lead.