Isaiah 43:26

Put me in remembrance; let us plead together: declare thou, that thou mayest be justified.  

When we pray, God says to put Him in remembrance of His word, not because He needs reminding, but for us to remember the promises of God.   By praying the scripture, we are praying specifically for the need.  Our focus is clear and our belief that the promise is ours because the word says so.  We are justified because we are praying, according to the word of God.