דברי הימים א יב:ט פירוש: רש״י

to the stronghold of the desert to the strongholds of the desert where he hid from Saul, as it is written (I Sam. 23:24): “And they arose and went to Ziph before Saul, and David and his men were in the desert of Maon, in the plain,” and it is written (ibid. 24:1): “And David went up from there, and he stayed in the strongholds of En-Gedi.”

and whose faces were [like] the faces of lions Their faces were frightful like lions.

and as swift as gazelles on the mountains They were swift in their running, for it is customary for gazelles to run on the mountains when people hunt them.