Question:If the first person sits down in the doorway and fills its, and a second comes and sits down at this side, even if the first rises and departs, the first is chayab and the second is patour.And the reason for that , is the mysay Sedah was already done by the first person. If we carry this logic through, it would seem that a person helping another in performing a melacha would be exempt. For example, a person carrying a load from one reshut to another and someone comes to give him a hand , the action was already done, the first person is still violating the Shabath ,but the second is patour!
Is the Issur of doing melacha is a continuous process as long as the violation action is continuously done. Such as the guarding of the door to prevent the animal from escaping. So helping in this action ,even undirectly should it not be an issure or a tolda of the Seida melacha?
When the animal is being guarded within the house, that is not considered as though the Melachah of trapping is constantly being performed every moment. The Mishnah (106a) says that one who captures a Zvi that is already inside a house is Patur. We see from there that the act of trapping occurs only at the moment that the exit from the house is blocked for the first time. After that, the animal is considered trapped and the person blocking the doorway is no longer performing a Melachah of trapping.
Accordingly, this case cannot be compared to the case of helping someone carry something to Reshus ha'Rabim, because there, the person is still involved with the act of the Melachah since he has not yet placed the object down.
Thanks, and be well,
-Mordecai