[Minutes of the Seventies]
My dear President [Heber J.] Grant:
... you gave to the apparent incongruity of the First Council of the Seventy being unable to participate with members of the Twelve when out in conferences, when ordaining High Priests and bishop's counselors when occasion should arise. The answer to all this has been that the Presidency of the Seventies, not being High Priests were barred from these functions; also in regard to performing marriage ceremonies, etc. Perhaps you will remember that I said I thought the decisions that had led to this policy of excluding the Seven Presidents from such functions was too tightly drawn and that if it were considered that these brethren have an APOSTOLIC CALLING, that calling would warrant them to do along these lines whatsoever might be necessary in the course of their ministry (as stated in Doctrine and Covenants) ...
I trust you will not think me over persistent in the matter, but I did think that since this information had come into my hands and also is in strict harmony with the interpretation I gave with the Seventies holding an APOSTOLIC CALLING, it would authorize the First Council to do whatever the Apostles do when necessary, and when appointed to do it, should be made known to you and your counselors and to the present quorum of the Twelve; and in this spirit I submit it to your consideration.
Very truly yours,
[Minutes of the Apostles of The Church of Jesus Christ of Latter-day Saints 1835-1951, Electronic Edition, Privately Published, Salt Lake City, Utah, 2015, Appendix 1: Minutes of the Seventies, 1837-1933, Excerpts]