D&C 93

After learning from the testimony of John that the Savior -

"...received not of the fulness at the first, but received grace for grace;
13 And he received not of the fulness at first, but continued from grace to grace, until he received a fulness..."  (Doctrine and Covenants | Section 93:12 - 13)

And upon bearing testimony that the Savior received a "fulness" of the glory of the Father, he then testifies to us -

"...that if you are faithful you shall receive the fulness of the record of John.
19 I give unto you these sayings that you may understand and know how to worship, and know what you worship, that you may come unto the Father in my name, and in due time receive of his fulness.
20 For if you keep my commandments you shall receive of his fulness, and be glorified in me as I am in the Father; therefore, I say unto you, you shall receive grace for grace."  (Doctrine and Covenants | Section 93:18 - 20)

To better understand this potential, we learn that in the pre-mortal life, the Savior said -

"...I was in the beginning with the Father, and am the Firstborn;
22 And all those who are begotten through me are partakers of the glory of the same, and are the church of the Firstborn.
23 Ye were also in the beginning with the Father; that which is Spirit, even the Spirit of truth..."  (Doctrine and Covenants | Section 93:21 - 23)

Which truth is defined as -

"...truth is knowledge of things as they are, and as they were, and as they are to come..."  (Doctrine and Covenants | Section 93:24)

So in the pre-mortal existence, we were also spirits, where -

"Man was also in the beginning with God...."  (Doctrine and Covenants | Section 93:29)

"For man is spirit. The elements are eternal, and spirit and element, inseparably connected, receive a fulness of joy;
34 And when separated, man cannot receive a fulness of joy.
35 The elements are the tabernacle of God; yea, man is the tabernacle of God, even temples; and whatsoever temple is defiled, God shall destroy that temple."  (Doctrine and Covenants | Section 93:33 - 35)

Thus we were spiritual offspring of Heavenly Parents with the plan to receive bodies of flesh and bone (elements) which will allow us to receive the fulness of our Heavenly Parents if we are faithful and keep His commandments.

That is why, Paul taught -

The Spirit itself beareth witness with our spirit, that we are the children of God:
17And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together.  (New Testament | Romans 8:16 - 17)