Joseph Smith's Response to Presenting Temple Ceremonies
Joseph has sense of urgency to present the temple endowment to the twelve prior to the completion of the Nauvoo Temple.
In 1842, Orson Hyde, of the Twelve Apostles, wrote of the following:
"We were in council with Brother Joseph almost every day for weeks; said Brother Joseph in one of those councils, 'There is something going to happen; I don't know what it is, but the Lord bids me to hasten and give you your endowment before the Temple is finished.' He conducted us through every ordinance of the holy priesthood, and when he had gone through with all the ordinance he rejoiced very much, and said, 'Now if they kill me, you have got all the keys, and all the ordinances, and you can confer them upon others, and the hosts of Satan will not be able to tear down the kingdom as fast you will be able to build it up'; and now, said he, 'On your shoulders will the responsibility of leading this people rest.'"
4 May 1842, Joseph recorded:
"I spent the day in the upper part of the store...in council with [seven brethren], instructing them in the principles and order of the Priesthood, attending to washings, anointings, endowments and the communication of keys pertaining to the Aaronic Priesthood, and so on to the highest order of the Melchisedek Priesthood, setting forth the order pertaining to the Ancient of Days, and all those plans and principles by which any one is enabled to secure the fullness of those blessings which have been prepared for the Church of the First Born, and come up and abide in the presence of the Eloheim in the eternal worlds.... The communications I made to this council were of things spiritual, and to be received only by the spiritual minded: and there was nothing made known to these men but what will be made known to all the Saints of the last days, so soon as they are prepared to receive, and a proper place is prepared to communicate them, even to the weakest of the Saints; therefore let the Saints be diligent in building the Temple."

Source:
Times and Seasons, vol. 5, p. 651.
History of the Church, Volume 5:1-2