The enclosure into which the sheep were usually brought for the night to protect them from thieves and predators. Although caves and other natural shelters were also used, often sheepfolds were permanent pens having stone walls (Num. 32:16; 1 Sam. 24:3; Zeph. 2:6) and an entranceway. (John 10:1) As in more recent times, the branches of thorny plants may have covered the tops of the stone walls. There may also have been low, flat buildings on the protected side of the enclosure, where the sheep were sheltered in severe weather. Whereas the flocks of several shepherds might be kept in the same sheepfold, there was no danger of confusion. The sheep responded only to the voice of their respective shepherd. A doorkeeper served at the entranceway of the sheepfold and opened to the shepherds in the morning.—John 10:2-4.