Whosoever perisheth, perisheth unto himself...for behold, ye are free. Through the atonement all mankind has been given agency and we are free to act for ourselves.
Those who receive the Lord and His Father will also receive their servants, the prophets. And if you receive God and His servants you will inherit all that the Father has. This is the "oath and covenant of the priesthood."
Men and women have power in themselves. We are agents and can bring to pass much good. As such, we ought to be "anxiously engaged." God is not pleased with those who are slothful and wait to be commanded in all things.
Those who reject or criticize the prophets will are severed from the ordinances of the temple, will not temporally prosper, will be despised by those who once flattered them, and will be cut off from the rights of the priesthood
Whatever the Lord's servants speak when they are moved upon by the Holy Ghost is scripture and will be the mind and will of the Lord and the power of God.
To gain a testimony of Jesus is to have the spirit of prophecy. Having the spirit of prophecy constitutes being a prophet.
A Seer is greater than a prophet, but is also a prophet and a revelator. A seer is able to reveal things that are past, future, hidden, and yet unknown.
D&C 21:4-6, 9
The Lord has commanded his church to receive the words of the prophet "as if from mine own mouth." If we do that he has promised us that the "gates of hell shall not prevail against you" and the "powers of darkness" will be dispersed before us.
. D&C 124:45-48
If we do not hearken unto the voice of the men whom God has appointed to preside over us, we will not be blest and instead of blessings we will receive "cursings, wrath, indignation, and judgments" upon our heads because we do not obey the prophets.
The Lord always has and always will reveal his secrets (His mind and will) to man through His chosen prophets.
2 Nephi 9:28-30
To be learned is good if one will hearken unto the precepts of God. It is foolishness to rely only on mortal learning.
The keys of the priesthood belong to the First Presidency, and the counselors are equal to the President in holding those keys.
Other than the prophet there is none other appointed unto you to receive commandments and revelations. So, in order to avoid being deceived, don't receive/accept the teachings of any that shall come before you as revelations or commandments. They are not of me.
There is never but one man on the earth on whom the Lord has given the power to hold and exercise all the keys of the priesthood.
2 Nephi 29:3, 9-10
Some in the last days may feel that they have all of God's words in the Bible. Since there are more nations than one, God has commanded men everywhere to write the words that He speaks to them. He will continue to speak until His work is finished.
2 Chronicles 20:20
Believe in the Lord your God, so shall ye be established; believe his prophets, so shall ye prosper. In order to put our trust in the Lord we can believe the words of His prophets.