The meaning is obvious, that you are the great Messiah, whose time is not wasted. That means that Hazrat Masih Maud a.s. put every second of his life available to him in the service of Allah. Yet he sometimes perhaps was worried about some time having been lost. He was eating, he was sleeping as well, he was resting sometimes, he was talking to children. So something must have been lying heavy on him, about which Allah wanted him to be put to rest.
So he said that although you have done everything in your power to sacrifice your time, every morsel of your time for my sake, yet I see you are not completely happy and content. You feel perhaps that a part thereof may have been wasted. But I know you and I tell you, this is a glad tiding from you, that as I see not a single second of your life is wasted and everything is being put into the service of Allah.
This is a reassurance from Allah and that also tells a story, untold story, of what passed in the mind and heart of Hazrat Masih Maud a.s. before this revelation.
