Consider these two quotes from the Prophet Joseph Smith:
#1 - "I frequently rebuke and admonish my brethren, and that because I love them, not because I wish to incur their displeasure, or mar their happiness. Such a course of conduct is not calculated to gain the good will of all, but rather the ill will of many; therefore, the situation in which I stand is an important one; so, you see, brethren, the higher the authority, the greater the difficulty of the station; but these rebukes and admonitions become necessary, from the perverseness of the brethren, for their temporal as well as spiritual welfare. They actually constitute a part of the duties of my station and calling. Others have other duties to perform, that are important, and far more enviable, and may be just as good, like the feet and hands, in their relation to the human body--neither can claim priority, or say to the other, I have no need of you. After all that has been said, the greatest and most important duty is to preach the Gospel. (Teachings of the Prophet Joseph Smith, Section Two, p. 112)
#2 - "The greatest responsibility in this world that God has laid upon us is to seek after our dead. The Apostle says, "They without us cannot be made perfect;" (Hebrews 11:40) for it is necessary that the sealing power should be in our hands to seal our children and our dead for the fulness of the dispensation of times--a dispensation to meet the promises made by Jesus Christ before the foundation of the world for the salvation of man. Now, I will speak of them. I will meet Paul half way. I say to you, Paul, you cannot be perfect without us. It is necessary that those who are going before and those who come after us should have salvation in common with us; and thus hath God made it obligatory upon man. Hence, God said, "I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord; and he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse." (Malachi 4:5-6.)" (Teachings of the Prophet Joseph Smith, Section Six 1843-44, p.356)
What is the link between these two most important efforts?