Is Satan omnipresent? If yes, how do we understand Job 1:6-7? If not, can we say when Satan is tempting somebody, everyone else is safe?
"And the LORD said to Satan, "From where do you come?" So Satan answered the LORD and said, "From going to and fro on the earth, and from walking back and forth on it"" (Job 1:7).
To say that God is omnipresent is to state that wherever we are, God is there. "Where can I go from Your Spirit? Or where can I flee from Your presence? If I ascend into heaven, You are there; If I make my bed in hell, behold, You are there. If I take the wings of the morning, and dwell in the uttermost parts of the sea, even there Your hand shall lead me, and Your right hand shall hold me. If I say, "Surely the darkness shall fall on me," even the night shall be light about me; indeed, the darkness shall not hide from You, but the night shines as the day; the darkness and the light are both alike to You" (Psalms 139:7-12). Thus, we are not saying that God can get someplace quickly, but that there is no place you can go and leave Him behind.
There is no similar statement regarding Satan. The fact that Satan talks about moving around on the earth is a clue that Satan is limited in this realm. Still, since he is a spirit, I would not know how quickly he can move. But to say that Satan only tempts one person at a time would be false. I sometimes sit at this computer working on a lesson while having chats with two people. True, I don't switch real fast, but still people on the other end see a continuous conversation and perhaps suspect a slow Internet connection.
Satan can set up many temptations and let them play out at the same time. Plus, you cannot forget that Satan is not working alone. "Then He will also say to those on the left hand, 'Depart from Me, you cursed, into the everlasting fire prepared for the devil and his angels"" (Matthew 25:41).