There are all sorts of self-imposed constraints on what each person is able to receive from heaven.[1] It is much easier to receive a gospel truth from another living person than from heaven directly (though, in all cases, it must still come through God's voice to you--your conscience--or you won't/shouldn't believe it).[2]
A living person can act as a living seer stone [3] up to the degree to which they have the spirit of God and are free from constraints, but what you receive directly from heaven will be limited to your understanding, sacrifice, faith, trust in God, and so on.[4]
If you find someone with greater understanding, sacrifice, faith, trust in God, and so on,[5] you have found a "window of heaven" larger than your own.[6] The spirit will not fight against you to force you to receive revelation beyond your worthiness, but another person can, up to the limits of their love for you.[7]
[1]
12 I have yet many things to say unto you, but ye cannot bear them now.
13 Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come.
14 He shall glorify me: for he shall receive of mine, and shall shew it unto you.
15 All things that the Father hath are mine: therefore said I, that he shall take of mine, and shall shew it unto you. (John 16)
[2]
17 Verily I say unto you, he that is ordained of me and sent forth to preach the word of truth by the Comforter, in the Spirit of truth, doth he preach it by the Spirit of truth or some other way?
18 And if it be by some other way it is not of God.
19 And again, he that receiveth the word of truth, doth he receive it by the Spirit of truth or some other way?
20 If it be some other way it is not of God.
21 Therefore, why is it that ye cannot understand and know, that he that receiveth the word by the Spirit of truth receiveth it as it is preached by the Spirit of truth?
22 Wherefore, he that preacheth and he that receiveth, understand one another, and both are edified and rejoice together.
23 And that which doth not edify is not of God, and is darkness.
24 That which is of God is light; and he that receiveth light, and continueth in God, receiveth more light; and that light groweth brighter and brighter until the perfect day.
25 And again, verily I say unto you, and I say it that you may know the truth, that you may chase darkness from among you; (D&C 50)
[3]
4 To whom coming, as unto a living stone, disallowed indeed of men, but chosen of God, and precious,
5 Ye also, as lively stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ. (1 Peter 2)
[4]
And therefore, he that will harden his heart, the same receiveth the lesser portion of the word; and he that will not harden his heart, to him is given the greater portion of the word, until it is given unto him to know the mysteries of God until he know them in full. (Alma 12:10)
2 ...and they had waxed strong in the knowledge of the truth; for they were men of a sound understanding and they had searched the scriptures diligently, that they might know the word of God.
3 But this is not all; they had given themselves to much prayer, and fasting; therefore they had the spirit of prophecy, and the spirit of revelation, and when they taught, they taught with power and authority of God.
4 And they had been teaching the word of God for the space of fourteen years.... (Alma 17)
For he that diligently seeketh shall find; and the mysteries of God shall be unfolded unto them, by the power of the Holy Ghost, as well in these times as in times of old, and as well in times of old as in times to come; wherefore, the course of the Lord is one eternal round. (1 Nephi 10:19)
Yea, he that repenteth and exerciseth faith, and bringeth forth good works, and prayeth continually without ceasing—unto such it is given to know the mysteries of God; yea, unto such it shall be given to reveal things which never have been revealed; yea, and it shall be given unto such to bring thousands of souls to repentance, even as it has been given unto us to bring these our brethren to repentance. (Alma 26:22)
[5]
31 And the office of their ministry is to call men unto repentance, and to fulfil and to do the work of the covenants of the Father, which he hath made unto the children of men, to prepare the way among the children of men, by declaring the word of Christ unto the chosen vessels of the Lord, that they may bear testimony of him.
32 And by so doing, the Lord God prepareth the way that the residue of men may have faith in Christ, that the Holy Ghost may have place in their hearts, according to the power thereof; and after this manner bringeth to pass the Father, the covenants which he hath made unto the children of men. (Moroni 7)
[6]
Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the Lord of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it. (Malachi 3:10)
[7]
Greater love hath no man than this, that a man lay down his life for his friends. (John 15:13)
5 And hope maketh not ashamed; because the love of God is shed abroad in our hearts by the Holy Ghost which is given unto us.
6 For when we were yet without strength, in due time Christ died for the ungodly.
7 For scarcely for a righteous man will one die: yet peradventure for a good man some would even dare to die.
8 But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us. (Romans 5)
This is my commandment, That ye love one another, as I have loved you. (John 15:12)