A properly calibrated compass can help the captain to keep the ship on course. Our conscience can be likened to a moral compass.
فَأَنْعَمَ عَلَيْهِ بِهِبَاتٍ كَثِيرَةٍ ،‏ وَأَحَدُهَا هُوَ ٱلضَّمِيرُ .‏