“The concluding phrase of v 13 (‘where Satan dwells’) is a contrast with the first clause in the verse (‘I know where you dwell’) in order to accentuate the idea that light and darkness cannot dwell together in peaceful coexistence. Therefore, a witnessing church will be a persecuted church.” (G. K. Beale, The Book of Revelation, NIGTC, p. 247).
“The name is known only to the recipient, just as the name of the Word of God, who rides a white horse, is known only to himself (Rev. 19:12-13). The name is a shared secret between the Lord and the recipient, blending mystery and disclosure.” (Dennis E. Johnson, Triumph of the Lamb, p. 78).
(Quotes used in the Reflection for Trinity Presbyterian Church.)