Jesus describes the degree of righteousness He desires from us in Matthew 5:17-48. He emphasizes its preeminent importance in Matthew 6:33. All these verses are part of His Sermon on the Mount, which fills chapters 5, 6, and 7 of Matthew’s gospel.
That God has put His laws in your heart is stated in Romans 2:14-16 and also in Hebrews 8:8-12. This had been prophesied in Jeremiah 31:31-34.