The LORD said to Satan, “Have you considered My servant Job? For there is no one like him on the earth, a blameless and upright man, fearing God and turning away from evil.” [Job 1:8]
In the above verse, we see that the LORD honored Job as His servant. It was an honor to Job to be acknowledged as His servant, just like it is an honor for us to be called His children. Note that the LORD knew this servant by name, and was aware of his character. How many CEOs know their ground staff by name, let alone their character? The LORD knows those that are His.
Later in the story, the evil one was skeptical regarding Job, and wanted to prove the LORD wrong. But the LORD was confident that Job would pass the trial, and indeed Job passed the trial. The evil one might boast in causing men to fall, but there would always be faithful men like Job.