They said; that is: the messengers: "Our Lord"; that is: the One who, if there were no deterrent for us from lying against Him except His kindness towards us, it would be enough; "He knows"; that is: and for this reason He shows through our hands the signs; and protects us from those who plot against us; and this phrase is treated as an oath; and similarly to: "Allah bears witness" [Aal 'Imran: 18]; and when they confronted them with this exaggerated denial; they increased the emphasis of their response; so they said: "Indeed, we are to you"; that is: specifically; "messengers"; we did not come to you by mistake; nor with a lie; for the first is the beginning of a report; and these two are responses of denial; so He gave each what it deserves.