If properly trained, your conscience can be a great help in keeping you on the right course. It can serve as a compass.
فَٱلْكِتَابُ ٱلْمُقَدَّسُ هُوَ ٱلْخَرِيطَةُ ٱلَّتِي تُرْشِدُكَ إِلَى ٱلسَّبِيلِ ٱلَّذِي يَنْبَغِي أَنْ تَسْلُكَهُ .‏