Joseph Fielding Smith
"The promise made to us, if we will do these things, is that we shall always have his Spirit to be with us.
"No member of the Church can fail to make this covenant and renew it week by week, and retain the Spirit of the Lord. The Sacrament meeting of the Church is the most important meeting which we have, and is sadly neglected by many members. We go to this service, if we understand the purpose of it, not primarily to hear someone speak, important though that may be, but first, and most important, to renew this covenant with our Father in heaven in the name of Jesus Christ. Those who persist in their absence from this service will eventually lose the Spirit and if they do not repent will eventually find themselves denying the faith." (Church History and Modern Revelation, 1:122-23)
Joseph E. Taylor
"You partake of the ordinance in order that His Spirit may be with you. You cannot have spiritual life without it. You show me a person who from Sabbath to Sabbath, month to month, and year to year, absents himself from these sacred meetings of the Latter-day Saints, and I will show you a man from whom the Spirit of the Lord will be taken and he will become spiritually dead. Do you believe it? It seems to lay at the very foundation of your spiritual life and mine." (Collected Discourses 1886-1898, ed. by Brian Stuy, vol. 5, Joseph E. Taylor, Nov. 18, 1894)