9 And also when the time came that Moses should sleep with his fathers, he was grieved and distressed, and he sought of his Lord and entreated that he might pass over to the land of promise. And why, my beloved, was the righteous Moses grieved because he did not enter into the land of promise? Clearly, because he wished to go and be buried with his fathers, and not be buried in the land of his adversaries, in the land of Moab. For the Moabites hired Balaam the son of Beor to curse Israel.
Therefore Moses wished not to be buried in that land, lest the Moabites should come and take vengeance on him by taking up and casting forth the bones of that righteous man. And the Lord performed an act of grace towards Moses. For He brought him forth to Mount Nebo, and showed him all the land, making it pass before him. And as Moses gazed upon all the land, and gazed upon the mountain of the Jebusites where the Tabernacle was to dwell, he was grieved and wept when he saw the tomb in Hebron where his fathers Abraham, Isaac and Jacob were buried, that he should not be buried with them, nor his bones cast upon their bones, that he might rise along with them in the Resurrection.
But when he had seen all the land, his Lord encouraged him and said to him, “I myself will bury you and hide you, and none shall know your tomb.” So Moses died according to the word of the mouth of the Lord, and He buried him in a valley in the land of Moab over against Beth-Peor, where Israel had sinned, and no man has known his sepulchre unto this day. Two goodly benefits did his Lord accomplish for Moses in not making known his tomb to the children of Israel. He rejoiced that his adversaries should not know it, and cast forth his bones from his tomb; and in the second place, that the children of his people should not know it, and make his tomb a place of worship, for he was accounted as God in the eyes of the children of his people.
And understand this, my beloved, from hence, that when he left them and went up to the mountain, they said: — As for this Moses who brought us up from the land of Egypt we know not what has become of him. So they made them a calf and worshipped it, and they remembered not God Who brought them up from Egypt by means of Moses with a mighty hand and an uplifted arm. Because of this, God had respect unto Moses, and did not make known his tomb; lest, if He should make known his tomb, the children of his people might go astray, and make them an image, and worship it and sacrifice to it, and so by their sins disquiet the bones of the righteous man.
Source: Demonstrations (New Advent)