Oliver Cowdery was a schoolteacher, who had heard of Joseph Smith. Oliver believed in personal revelation, because he received it by using a divining rod. It is believed that he would ask "yes/no" type questions. In doing so, the rod would point up for "yes", and down for "no."
This rod was also known as a "rod of nature" or the "gift of Aaron." In the revelations we find that the Lord approved of Oliver using the divining rod as a method to receive revelation. The ability to receive revelation (at the time via the rod) was the gift the Lord had given him. From what we read in the sections, it seems Oliver used the rod to determine if Joseph was truly a prophet of God. The rod also seems to be the source of revelation to send him to Joseph and work as his scribe.
This brings the scriptures into a new context regarding the gift Oliver had:
"Behold thou hast a gift, and blessed art thou because of thy gift. Remember it is sacred and cometh from above—
And if thou wilt inquire, thou shalt know mysteries which are great and marvelous; therefore thou shalt exercise thy gift, that thou mayest find out mysteries, that thou mayest bring many to the knowledge of the truth, yea, convince them of the error of their ways.
Make not thy gift known unto any save it be those who are of thy faith. Trifle not with sacred things.
If thou wilt do good, yea, and hold out faithful to the end, thou shalt be saved in the kingdom of God, which is the greatest of all the gifts of God; for there is no gift greater than the gift of salvation.
Verily, verily, I say unto thee, blessed art thou for what thou hast done; for thou hast inquired of me, and behold, as often as thou hast inquired thou hast received instruction of my Spirit. If it had not been so, thou wouldst not have come to the place where thou art at this time." D&C 6:10-14
Just as Aaron, the brother of Moses, received power from God via two rods: the staff of Moses and the budding rod, so Oliver would also have this great gift.
"Verily, verily, I say unto you, if you desire a further witness, cast your mind upon the night that you cried unto me in your heart, that you might know concerning the truth of these things.Here, the Lord showed Oliver another way to receive revelation, through the Spirit speaking peace to his mind and heart. Oliver was then granted the gift of translation. However, Oliver was used to the idea of just asking a question and having his divining rod give a quick reply of yes/no. Translation through any means is a much more difficult and complex process. As we read in D&C 9, it required working it out in one's mind until one found a probable answer, and then asking if it is right (the yes/no question). Oliver skipped the first part. And it may be he did not understand how the Spirit works on the higher level of speaking to the mind and heart, as the Lord also had to explain this to him:
Did I not speak peace to your mind concerning the matter? What greater witness can you have than from God?
And now, behold, you have received a witness; for if I have told you things which no man knoweth have you not received a witness?
And, behold, I grant unto you a gift, if you desire of me, to translate, even as my servant Joseph." D&C 6:22-25
"Behold, you have not understood; you have supposed that I would give it unto you, when you took no thought save it was to ask me.
But, behold, I say unto you, that you must study it out in your mind; then you must ask me if it be right, and if it is right I will cause that your bosom shall burn within you; therefore, you shall feel that it is right.
But if it be not right you shall have no such feelings, but you shall have a stupor of thought that shall cause you to forget the thing which is wrong; therefore, you cannot write that which is sacred save it be given you from me.
Now, if you had known this you could have translated; nevertheless, it is not expedient that you should translate now." D&C 9:7-10
We should not be surprised that the Lord allows mankind to use props that can assist them in knowing God. Joseph Smith used both the Urim and Thummim and his seer stone in a hat. Moses and Aaron used his staff. Jesus once used clay to heal a blind man's eyes.
It is likely that Oliver used his divining rod less and less, as he learned to receive revelation without it, just as Joseph learned to receive revelations without his seer stone and the Urim and Thummim.