Who searches hearts and repays for deeds?

Revelation 2:18-23 NWT

“To the angel of the congregation in Thy·a·tiʹraj write: These are the things that the Son of God says, the one who has eyes like a fiery flame and whose feet are like fine copper: ‘I know your deeds, and your love and faith and ministry and endurance, and that your deeds of late are more than those you did at first. “‘Nevertheless, I do hold this against you, that you tolerate that woman Jezʹe·bel, who calls herself a prophetess, and she teaches and misleads my slaves to commit sexual immorality and to eat things sacrificed to idols. And I gave her time to repent, but she is not willing to repent of her sexual immorality. Look! I am about to throw her into a sickbed, and those committing adultery with her into great tribulation, unless they repent of her deeds. And I will kill her children with deadly plague, so that all the congregations will know that I am the one who searches the innermost thoughts and hearts, and I will give to you individually according to your deeds.

Who is speaking in Revelation 2:18-23?
Jeremiah 17:10 NWT

I, Jehovah, am searching the heart,
Examining the innermost thoughts,
To give to each one according to his ways
According to the fruitage of his works.

To search hearts and examine thoughts, what is required?
Why is Jesus saying what only Jehovah can do?
Why is Jesus speaking in the exact same way that Jehovah speaks?
Why is Jesus claiming the ability that Jehovah has?