John the Apostle
Revelation 3:2BSB·traditional attribution

Wake up and strengthen what remains, which is about to die; for I have found your deeds incomplete in the sight of My God.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. The preface, showing, 1. To whom this letter is directed: To the angel of the church of Sardis, an ancient city of Lydia, on the banks of the mountain Tmolus, said to have been the chief city of Asia the Less, and the first city in that part of the world that was converted by the preaching of John; and, some say...

Commenting on Revelation 3:1-6

John Gill Reformed Baptist @doctorgill

Be watchful,.... Which may respect both ministers and members: the ministers of the Gospel, whose business is to watch over themselves, their conversation and doctrine, and watch every opportunity to preach it, and the success of their ministry; and that they do not grow careless, or be drawn aside through frowns or flatteries; and over others, as shepherds do, to know the state of their...

Albert Barnes Presbyterian @notesbybarnes

Verse 2. Be watchful. Be wakeful; be attentive and earnest--in contradistinction from the drowsy condition of the church. Strengthen the things which remain. The true piety that still lives and lingers among you. Whatever there was of religion among them, it was of importance to strengthen it, that the love of the Saviour might not become wholly extinct.