D&C 33

To Ezra Thayre and Northrup Sweet, the Lord instructs -

"...open your mouths and they shall be filled, saying: Repent, repent, and prepare ye the way of the Lord, and make his paths straight; for the kingdom of heaven is at hand;
11 Yea, repent and be baptized, every one of you, for a remission of your sins; yea, be baptized even by water, and then cometh the baptism of fire and of the Holy Ghost."  (Doctrine and Covenants | Section 33:10 - 11)

And then He teaches -

"...verily, verily, I say unto you, this is my gospel; and remember that they shall have faith in me or they can in nowise be saved..."  (Doctrine and Covenants | Section 33:12)

And then He adds -

"...upon this rock I will build my church; yea, upon this rock ye are built..."  (Doctrine and Covenants | Section 33:13)

Obviously, the rock then is the gospel or the gospel of Jesus Christ which includes faith, repentance, baptism, and the gift of the Holy Ghost.  In His ministry in the Americas, the Savior taught the same thing -

"...that whoso repenteth and is baptized in my name shall be filled; and if he endureth to the end, behold, him will I hold guiltless before my Father at that day when I shall stand to judge the world.
17 And he that endureth not unto the end, the same is he that is also hewn down and cast into the fire, from whence they can no more return, because of the justice of the Father.
18 And this is the word which he hath given unto the children of men. And for this cause he fulfilleth the words which he hath given, and he lieth not, but fulfilleth all his words.
19 And no unclean thing can enter into his kingdom; therefore nothing entereth into his rest save it be those who have washed their garments in my blood, because of their faith, and the repentance of all their sins, and their faithfulness unto the end.
20 Now this is the commandment: Repent, all ye ends of the earth, and come unto me and be baptized in my name, that ye may be sanctified by the reception of the Holy Ghost, that ye may stand spotless before me at the last day.
21 Verily, verily, I say unto you, this is my gospel; and ye know the things that ye must do in my church..."  (Book of Mormon | 3 Nephi 27:16 - 21)

Herein the Savior adds "endure to the end".  Jacob taught that the gospel of Jesus Christ is the doctrine of Jesus Christ teaching his people -

"...the gospel, or the doctrine of Christ..."  (Book of Mormon | Jacob 7:6)

The gospel of Jesus Christ is also then the doctrine of Christ where again in the Savior's ministry in the Americas, He taught -

"...I will declare unto you my doctrine.
32 And this is my doctrine, and it is the doctrine which the Father hath given unto me; and I bear record of the Father, and the Father beareth record of me, and the Holy Ghost beareth record of the Father and me; and I bear record that the Father commandeth all men, everywhere, to repent and believe in me.
33 And whoso believeth in me, and is baptized, the same shall be saved; and they are they who shall inherit the kingdom of God.
34 And whoso believeth not in me, and is not baptized, shall be damned.
35 Verily, verily, I say unto you, that this is my doctrine, and I bear record of it from the Father; and whoso believeth in me believeth in the Father also; and unto him will the Father bear record of me, for he will visit him with fire and with the Holy Ghost.
36 And thus will the Father bear record of me, and the Holy Ghost will bear record unto him of the Father and me; for the Father, and I, and the Holy Ghost are one.
37 And again I say unto you, ye must repent, and become as a little child, and be baptized in my name, or ye can in nowise receive these things.
38 And again I say unto you, ye must repent, and be baptized in my name, and become as a little child, or ye can in nowise inherit the kingdom of God.
39 Verily, verily, I say unto you, that this is my doctrine, and whoso buildeth upon this buildeth upon my rock..." (Book of Mormon | 3 Nephi 11:31 - 39)

It is important to understand that the gospel of Jesus Christ is the doctrine of Christ which includes faith, repentance, baptism, receive the Gift of the Holy Ghost and endure to the end to be "spotless" at the last day.  And if we teach more than this to become spotless, we are not built upon His rock.