I am giving below some quotes from Brother Russell that shows that he believed Jesus to be the channel between God and man.
It was quite proper that these disciples did not follow the course that some are inclined to follow today, viz., to seek to learn of the Master all that he would communicate, and then go forth and pose as wise ones amongst their friends, giving them the information they had received in driblets, and avoiding the mention of Jesus as the Father's channel of communication of the truth to them. -- "We Have Found Him! Eureka!", Watch Tower, February 1, 1900.
None have life in a legal sense except those who have obtained it from God through His provided channel Christ Jesus. -- "From Death to Life in Christ", Harvest Gleanings III.
All resolutions against sin and in favor of righteous thinking and living are commendable and helpful. But I recommend a comprehensive resolution; namely, to get right with God through His appointed Channel, the Lord Jesus Christ, and through the instructions of His Word, the Bible. -- "A New Epoch Starts", Harvest Gleanings III.
God purposed to allow sin to demonstrate for six thousand years its awful fruitage, and then to bring in a great Sabbath Day, the great Millennial Sabbath of a thousand years, and in that time to do a work for mankind which they cannot do for themselves. He is to do this work through Jesus, His appointed Channel. -- "New Creatures Perfect in Holiness", Harvest Gleanings III.
Only as the Heavenly Father shall grant His blessing may fruits to our labors be expected. It is written, "As many as the Lord your God shall call," and "No man can come unto Me except the Father who sent Me draw him." (Acts 2:39; John 6:44) Hence we see that our present appreciation of Divine goodness implies three gifts: (1) The Divine provision of eternal life, (2) Christ the Channel, and (3) the knowledge by which we are enabled to appreciate both the Gift and the Channel. -- "Christ Our Propitiation", Watch Tower, December, 1882.
The channel of all of God's Mercy is Christ Jesus, who declared, "No man cometh unto the Father but by Me." Of Him also St. Peter said, "Neither is there salvation in any other, for there is none other name under Heaven given amongst men, whereby we must be saved." (Acts 4:12.) -- "Hope for the Sodomites", Watch Tower, February 1, 1913.
If anyone finds more that could be placed here, please respond in the comments below.
Who Did Russell Believe to be the "Only Authority" of the Church?
What Did Russell Teach About "Organization" as Related to the Watch Tower Society?