Allah (SWT) mentioned in surah AR-RUM that from amongst the signs of Allah (SWT) i.e. which indicates the greatness, grandeur, and majesty of Allah, signs which are indicative of the oneness of Allah (SWT). Amongst those signs is that he has created from you “mates” so that you may find rest in her and he has made between you love and mercy indeed this (marriage) is a sign for those who think.