The language of God’s covenantal blessing upon those who “hear and keep” the word/law of God in Revelation 1:3 draws upon the same language found in Deuteronomy 5:1; 6:3; 28:1-2. Therefore, the summary purpose statement of the entire Apocalypse that is found in the opening preface (Rev 1:3) is a Deuteronomic exhortation for Israel to remain loyal to the eternal covenant.
The Book of Revelation is an exhortation to keep the law of Moses despite tribulation
Immanuel Bible Institute 