Shabbos Daf 5 שבת דַף 5

Rav said that one who transports an object four amos in a roofed reshus harabim [on Shabbos] is exempt since it does not resemble the encampment in the wilderness(דגלי מדבר).

Rava said that a person’s hand is as significant to him as an area of four by four tefachim. Even though it is narrower than four tefachim, it can hold very large objects due to its grasping nature (Rambam).

This explains why the poor man, when he places the object in the householder’s hand, it is as if he placed it upon an area that is four by four tefachim wide.

Rav Yochanan taught that if one lifted food and drink in one corner of a reshus hayachid with the intent on carrying it to another corner of the private domain and then changed his mind walked in and out all day long, he is not liable until he stands still momentarily and then continues walking.

Since the עקירה is an essential part of the melochoh, it has to be done with intent.

Abaye qualifies this ruling and says that he is liable only if he stood to rest. If he stood merely to adjust his load it is not considered as if he stopped walking.