He and his wife self proclaimed that identity via Scripture but the truth of the matter he was more faithful to his own acquired theology which he mostly derived from other outside sources ie. Pyramidology
He was actually more faithful and wise to his publishing house Zion's Watchtower which he started.
Real bible theologians of the time scoffed at his theological findings, Russell was more of a novice.
Other Evangelical preachers of the era including Russell obviously didn't read the words of Jesus very well when he said .. " that no one knows of the time or hour and admonished his true followers to not set a time upon god's own sacred time ".