Luke 10:24

“For I say to you, that many prophets and kings desired to see the things which you see, and did not see them, and to hear the things which you hear, and did not hear them.”

This was something that many wise men of understanding, many prophets and kings, have desired to see, and have not seen it, have desired to hear and have not heard it (compare 1 Peter 1:10; Isaiah 52:15). They saw it in part but they could not know. But they, the disciples, have heard it and seen it and are therefore truly blessed. This is therefore what they should primarily rejoice in. Note the introduction of the idea of ‘hearing'. Hearing His words is constantly central in Jesus thinking. Having ‘seen' Him as the beloved Son they must hear Him in His role as the introducer of the last days, of the acceptable year of the Lord (Luke 4:19), as the revealer of the mind of God.