Psalm 44
What God had done for Israel was passed on from generation to generation. In particular they reminded the people that it was because of God that they had possession of the land and had defeated the nations.
Verse 4 declares that God is their God, so they put no trust in human strength. So they make God their boast. Nations so often boast in their own strength or resources, we should be careful not to do this, but to boast in the Lord.
However, it seemed that God had rejected them, and their enemies were defeating them. In verse 17 the psalmist ( not David in this case) they claim that they had not forgotten God. They call on God to act on their behalf. There are times when it seems that God has forgotten us, or is even against us, even though we don’t think we have been unfaithful. Whatever the case we should call upon the Lord. If we have indeed sinned He will make it clear to us, if not He will act on our behalf.