D&C 29

Throughout the scriptures, we find a doctrine commonly known as "Divine investiture" where an angel or the Savior speaks as the divine entity they are representing.  This is apparent in this revelation where the Savior begins -

"LISTEN to the voice of Jesus Christ, your Redeemer, the Great I AM, whose arm of mercy hath atoned for your sins;
2 Who will gather his people even as a hen gathereth her chickens under her wings, even as many as will hearken to my voice and humble themselves before me..."  (Doctrine and Covenants | Section 29:1 - 2)

Then adds as if He is the Father saying -

"...and call upon me in mighty prayer."  (Doctrine and Covenants | Section 29:2)

We know He is speaking as the Father in that He has already instructed the people in the Americas -

"...ye must always pray unto the Father in my name..."  (Book of Mormon | 3 Nephi 18:19)

This becomes even more apparent as later in this revelation, the Savior says twice -

"...through faith on the name of mine Only Begotten Son."  (Doctrine and Covenants | Section 29:42)

And again -

"...little children are redeemed from the foundation of the world through mine Only Begotten..."  (Doctrine and Covenants | Section 29:46)

Elder Bruce R. McConkie explained -

“CHRIST MAY SPEAK AS THE FATHER. In giving revelations our Savior speaks at times for himself; at other times for the Father, and in the Father’s name, as though he were the Father, and yet it is Jesus Christ, our Redeemer who gives the message. So, we see, in Doctrine and Covenants 29:1, that he introduces himself as ‘Jesus Christ, your Redeemer,’ but in the closing part of the revelation he speaks for the Father, and in the Father’s name as though he were the Father, and yet it is still Jesus who is speaking, for the Father has put his name on him for that purpose.” (Joseph Fielding Smith, Doctrines of Salvation, 3 vols., edited by Bruce R. McConkie [Salt Lake City: Bookcraft, 1954–56], 1:27.)