‘And there came a cloud overshadowing them, and there came a voice from the cloud, “This is my beloved Son, listen to Him.”
The appearance of Moses and Elijah was followed by an overshadowing cloud which was testimony to the fact that God too had come to join the company (Exodus 19:9). It was once more a reminder of Moses in the mount of God (Exodus 24:18), but this time overshadowed Jesus, Moses and Elijah. This was their ‘booth'. They needed no other. And from the cloud came a voice to the disciples (compare Exodus 24:16; Psalms 99:7). And it made crystal clear to the three disciples the uniqueness of Jesus. For God testified to the fact that He was His ‘own beloved Son', and that He was the One Who must above all be listened to. He was greater than Moses, He was greater than Elijah. In Him came the full truth about God. All other messengers had been superseded.
The idea that Jesus was the Father's beloved Son had been emphasised after His baptism (Mark 1:11). It was apparent to the demon world (Mark 3:11; Mark 5:7). It is brought home to them here. It will be revealed in veiled form in the parable of the wicked tenants (Mark 12:6). And Rome acknowledges it at the cross (Mark 15:39). It runs like a golden cord through the narrative. This is God's beloved Son.
‘A cloud overshadowing them.' By the cloud God reveals His presence, yet veils it, and a cloud is regularly connected with the glory of God being revealed. (Exodus 19:9; Exodus 13:21-22; Exodus 14:19; Exodus 14:24; Exodus 24:15-16; Exodus 33:9-10; Exodus 40:34-38; 1 Kings 8:10-11; Ezekiel 10:3-4). Here it is the glory of Jesus that is revealed and then veiled by the cloud. The implication of His divinity is unmistakable.
‘My beloved Son.' See Mark 1:11. It would be some time before the full significance of this would dawn on the disciples, but from now on they had to recognise that He was like no other. He was truly the Messiah, but not only the Messiah, He had a unique relationship with the Father. ‘Beloved' reflects the fact that Jesus was not adopted by God like the kings of Israel but was unique. It practically reflects the same idea as the ‘only begotten' - it is used in LXX to indicate Abraham's ‘only son' and Jephthah's ‘only daughter' - but was especially suitable as distinguishing Jesus from the earlier Davidic kings, as the One Whom God essentially and uniquely loved, His only beloved Son, Whose relationship with God was like no other (compare Mark 12:6).
‘Listen to Him.' Listen is a strong expression and means take notice and obey, for He is the ‘Prophet like Moses' who was to come. It echoes Deuteronomy 18:15. (See Deuteronomy 18:15 with Deuteronomy 18:18-19). Moses and Elijah are not now required for He is the One Who is greater than all, and if men will not hear Him they will hear no one. The idea of the Prophet like to Moses was linked in 1st century Judaism with Messianic expectations.