Jesus reminded the Christians in Thyatira that he is the sovereign appointed by the Father after ascending to heaven. He mentions this appointment when referring to the authority he will yet give to his people. The position Jesus has is connected to his role as the Mediator. He has been given supreme authority as a reward for his work on the cross and he reigns over all things in order to gather in his people from all periods of history.
Jesus also reminded the church in Thyatira that he is the searcher of hearts. He can do this because he is divine, possessing all the attributes of God, one of which is omniscience. When he searches the hearts of his people, there is nothing that they can hide from him. From one point of view, this would be frightening, but we should remember that he also comes as the good physician to heal what is wrong with us. It is better to have a Saviour who sees all our faults than to have one who did not know our defects.
And Jesus speaks here of his works that his followers have to hold on to. Those works also seem to be their works that he approved of earlier in the letter, which he said were increasing in number and flowed from love. Those works were done in obedience to his commandments. We could say that those works are done for him initially because of his grace and are then appropriated by him to bring blessings to others.