The brook Cedron - This was a small stream that flowed to the east of Jerusalem, through the valley of Jehoshaphat, and divided the city from the Mount of Olives. It was also called Kidron and Kedron. In summer it is almost dry. The word used here by the evangelist - χειμάῤῥου cheimarrou - denotes properly a water-stream (from χεῖρμα cheimōn, shower or water, and ῥέω reō, ῥόος roos, to flow, flowing), and the idea is that of a stream that was swollen by rain or by the melting of the snow (Passow, Lexicon). This small rivulet runs along on the east of Jerusalem until it is joined by the water of the pool of Siloam, and the water that flows down on the west side of the city through the valley of Jehoshaphat, and then goes off in a southeast direction to the Dead Sea. (See the map of the environs of Jerusalem.) Over this brook David passed when he fled from Absalom, 2 Samuel 15:23. It is often mentioned in the Old Testament, 1 Kings 15:13; 2 Chronicles 15:16; 2Ch 30:14; 2 Kings 23:6, 2 Kings 23:12.
Where was a garden - On the west side of the Mount of Olives. This was called Gethsemane. See the notes at Matthew 26:36. It is probable that this was the property of some wealthy man in Jerusalem - perhaps some friend of the Saviour. It was customary for the rich in great cities to have country-seats in the vicinity. This, it seems, was so accessible that Jesus was accustomed to visit it, and yet so retired as to be a suitable place for devotion.