Among Ar-Rum's signs of creation is a verse that became, independently of the surah's prophecy and cosmological argument, the passage most commonly recited at Muslim wedding ceremonies across many cultures: 'among His signs is that He created for you mates from among yourselves, that you may find tranquillity in them, and He placed between you love and mercy' (30:21). Marriage sermons and devotional wedding literature cite the verse as the primary Quranic statement on the purpose and emotional character of marriage, naming tranquillity, love and mercy rather than only procreation or social contract as its stated aims.
Classical commentary reads the verse within its surrounding argument, that pairing itself, like sleep, like the diversity of languages and colours, is presented as a sign pointing toward its Creator rather than as legislation, distinguishing this poetic statement of marriage's purpose from the Quran's separate legal material on marriage contracts, rights and obligations found in surahs such as An-Nisa and At-Talaq. Its devotional prominence rests less on legal content than on the emotional vocabulary it supplies, tranquillity, love and mercy, terms later Islamic marital counsel and popular teaching return to repeatedly when describing the ideal character of a marriage.