A.T. Robertson Commentary Revelation 3:5

"He that overcometh shall thus be arrayed in white garments; and I will in no wise blot his name out of the book of life, and I will confess his name before my Father, and before his angels." — Revelation 3:5 (ASV)

Shall be arrayed (περιβαλειτα). Future middle indicative of περιβαλλω, to fling around one, here and in 4:4 with εν and the locative, but usually in this book with the accusative of the thing, retained in the passive or with the middle (7:9,13; 10:1; 11:3; 12:1; 17:4; 18:16; 19:8,13).

In white garments (εν ιματιοις λευκοις). Apparently the spiritual bodies in the risen life as in 2 Corinthians 5:1,4 and often in Revelation (3:4,5; 6:11; 7:9,13f.; 19:8).

I will in no wise blot out (ου μη εξαλειψω). Strong double negative ου μη and the first aorist active (or future) of εξαλειφω, old word, to wipe out (Acts 3:19).

Of the book of life (εκ της βιβλου της ζωης). Ablative case with εκ. This divine register first occurs in Ex 32:32f. and often in the O.T. See Lu 10:20; Php 4:3; Revelation 13:8; 20:15; 21:27. The book is in Christ's hands (13:8; 21:27).

His name (το ονομα αυτου). The name of the one who overcomes (ο νικων). Clear reminiscence of the words of Christ about confessing to the Father those who confess him here (Matthew 10:32; Luke 9:26; Luke 12:8). Whether John knew the Synoptic Gospels (and why not?) he certainly knew such sayings of Jesus.