سَلَٰمٌ قَوۡلًا مِّن رَّبٍّ رَّحِيمٍ
"Peace!" - a word (of salutation) from a Lord Most Merciful!<br/>
"Peace!" (salaamun is a subject) - the word (qawlan is its predicate), that is, [peace] by way of a word, from a Lord [Who is] Merciful, to them, in other words, He says to them, 'Peace be on you!'