Exodus 14:14--The Lord will fight for you, you need only be still (told to the Israelites as they were leaving Egypt.)
Deutoronomy 1:30,31--The LORD your God, who is going before you, will fight for you, as he did for you in Egypt, before your very eyes and in the desert. There you saw how the LORD your God carried you, as a father carries his son, all the way you went until you reached this place."(Told to the Israelites as they were about to enter the promised land)
Deut. 3:22--Do not be afraid of them; the Lord your God himself will fight for you (moses told Joshua this as he was about to take possession of the promised land)
I was reminded of these verses this week, as I struggled to recall God's faithfulness to me.
These verses not only remind me that the Lord will fight for me and be faithful (because that is His character--He cannot change), but also how often the Israelites needed reminded of the same truth because of their unbelief. How quickly they forgot, which is sad, actually. What more did they want? He showed Himself faithful time and again, yet they were quick to forget, quick to question, quick to show unbelief.
How often I am like them. How foolish I am. What more do I want? He will fight for me, defend me, never leave me. I am resolved to remember, resolved to believe, resolved to trust.
Satan loves to make us forget what we should remember (the past victories and miracles of God on our behalf) and loves to make us remember what we should forget (our past of sin and the self-life).
...In essence, it was not sin that kept Israel out of the Promised Land, it was unbelief (though certainly, unbelief is sin). Israel's sin could be covered through atoning sacrifice; but unbelief, and doubt of God's love for them, made them unable to trust God at all.
We often think that it is really some sin that hinders us from going on with the Lord. It is true that the Lord wants to deal with the sin and get it out of the way, but the way that happens is by deepening the relationship of love and trust in the Lord. Unbelief and lack of trust is the real enemy!
~David Guzik's Commentary on Deut. 1:30, 31