so that is the essence between the Christian and Jewish view of
satan.
nobody thinks of satan as their good friend, but how does God view
satan? As a rebel? Or as His servant?
You have to see the big picture, angels are messengers/servants of
God. They are absolutely loyal; you can even think of them as no
free will.
If you think angels can rebel (and worse .. xtians say 1/3 of
angels rebelled with satan?) .. then what is stopping the rest who
haven't rebelled in the past to rebel now? There is nothing to stop
everyone's favourite Michael and Gabriel to rebel.
Now zoom in on the role of angels - they are first and foremost
messengers. Will God create the angelic species with the propensity
to rebel or sin? What if Gabriel felt bo liao and purposely
mis-communicate that Mary is full of grace? What if Gabriel felt
lazy and didn't dictate the Qu'ran to the Prophet Muhammed
faithfully?
What if during armageddon, archangel Michael rebels and turns
against God? Instead of going to battle with satan's minons, he
betrays God. So li3 ying4 wai4 he2, the bad angels surround heaven
until shui3 xie4 bu4 tong1. 
