'Sin' by definition is anything against Allah!
However, when we think of the creation we sin because we have the freedom to choose between good and bad. Adam and Eve committed sin because of that freedom. If we assume that they sinned because of the tempter then this is not the case when Satan sinned while being in the very presence of Allah! Therefore, a free being/entity can commit sin even when that being/entity has no sinful nature internally or a sinful tempter externally.
All those who enter into Jannah or the presence of Allah and enjoy eternal life will have free-will. But the question is what makes them not to sin again like Satan?