he Lord can't reveal to you and I what we can't understand (Brigham Young)

 “The Lord can't reveal to you and I [what] we can't understand;…for instance when Joseph first received revelation, The Lord could not tell him what he was going to do. He didn't tell him he was going to call him to be a prophet, seer, revelator, high priest and founder of [the] Kingdom of God on the earth. Joseph would have said… ‘just what does that mean? You are talking that I can't understand.’ He could merely revealed to him that the Lord is pleased to bless him and forgive his sins and there was a work for him to do on the earth…

The first time He sent [an] angel to visit him, he could lead his mind a little further. He could reveal to him that there were certain records deposited on in the earth to be brought forth for the benefit of [the] inhabitants of the earth. He could reveal after this that Joseph could get them; then he could reveal that he should have power to translate the records from the language and characters in which it was written and give it to the people in the English language, but this was not taught him first…

After this he could tell him that he could receive the high priest had organized the church and so on. This is the way the Lord has to instruct all people on the earth. I make mention of this to show you that…the Lord can't teach all things to people at once. He gives [a] little here and a little there, revelation upon revelation upon revelation, a precept today, tomorrow another, the next day another. If the people make good use of it and improve upon what the Lord gives them he is ready to bestow more.” 

Brigham Young, Discourse 25 March 1855, Papers of George D. Watt, MS 4534, box 3, disk 1 images 142-53, transcribed by LaJean Purcell Carruth)(emphasis added)