Whispering of Shaitan does not need his physical presence in front of us, as Shaitan is able to whisper to us from far and we don't see him. Shaitan whispered to Adam and Eve and Talal oath that he is advising them for their benefit. They never thought that anyone can take a false oath. They did not commit any sin by eating from the tree because they were never been ordered but just been advised. Doing against an advice is not a sin but it was better to avoid it.

'Wassalam.