Tafsir of An-Naml 27:69

"Say: Travel through the earth and observe how was the end of the criminals"

This is on account of their rejecting the Messengers (peace be upon them) regarding that to which they invited them, namely belief in Allah (the Exalted and Majestic) alone and in the Last Day, which you deny. For in witnessing their end lies sufficient instruction for those of insight.

In referring to the deniers as "criminals"—a term that is more general in concept—there is a kindness shown to the believers, encouraging them to abandon crimes, as it guides them to the fact that crime, in an absolute sense, is abhorrent to Allah (the Exalted and Majestic).