Numbers 9

Moses records that -

"...on the day that the tabernacle was reared up the cloud covered the tabernacle, namely, the tent of the testimony: and at even there was upon the tabernacle as it were the appearance of fire, until the morning.

16 So it was alway: the cloud covered it by day, and the appearance of fire by night.
17 And when the cloud was taken up from the tabernacle, then after that the children of Israel journeyed: and in the place where the cloud abode, there the children of Israel pitched their tents.
18 At the commandment of the LORD the children of Israel journeyed, and at the commandment of the LORD they pitched: as long as the cloud abode upon the tabernacle they rested in their tents.
19 And when the cloud tarried long upon the tabernacle many days, then the children of Israel kept the charge of the LORD, and journeyed not.
20 And so it was, when the cloud was a few days upon the tabernacle; according to the commandment of the LORD they abode in their tents, and according to the commandment of the LORD they journeyed.
21 And so it was, when the cloud abode from even unto the morning, and that the cloud was taken up in the morning, then they journeyed: whether it was by day or by night that the cloud was taken up, they journeyed.
22 Or whether it were two days, or a month, or a year, that the cloud tarried upon the tabernacle, remaining thereon, the children of Israel abode in their tents, and journeyed not: but when it was taken up, they journeyed.
23 At the commandment of the LORD they rested in the tents, and at the commandment of the LORD they journeyed: they kept the charge of the LORD, at the commandment of the LORD by the hand of Moses."  (Old Testament | Numbers 9:15 - 23)

I think there is great symbolism with the cloud by day and fire by night.  In our own personal lives we have been given the Gift of the Holy Ghost which may serve even as this cloud of fire.  Nephi taught -

 "...if ye will enter in by the way, and receive the Holy Ghost, it will show unto you all things what ye should do."  (Book of Mormon | 2 Nephi 32:5)

Another point is that after sometime their seemed to be so much murmuring in the camp of Israel that even a discouraged -

"...Moses said unto the LORD, Wherefore hast thou afflicted thy servant? and wherefore have I not found favour in thy sight, that thou layest the burden of all this people upon me?
12 Have I conceived all this people? have I begotten them, that thou shouldest say unto me, Carry them in thy bosom, as a nursing father beareth the sucking child, unto the land which thou swarest unto their fathers?"  (Old Testament | Numbers 11:11 - 12)

Adding -

"...I am not able to bear all this people alone, because it is too heavy for me.

15 And if thou deal thus with me, kill me, I pray thee, out of hand, if I have found favour in thy sight; and let me not see my wretchedness."  (Old Testament | Numbers 11:14 - 15)

Again the Lord teaches the principle of delegation as He instructed -

"...Gather unto me seventy men of the elders of Israel, whom thou knowest to be the elders of the people, and officers over them; and bring them unto the tabernacle of the congregation, that they may stand there with thee.
17 And I will come down and talk with thee there: and I will take of the spirit which is upon thee, and will put it upon them; and they shall bear the burden of the people with thee, that thou bear it not thyself alone."  (Old Testament | Numbers 11:16 - 17)

As Moses followed these instructions, he records -

"...there remained two of the men in the camp, the name of the one was Eldad, and the name of the other Medad: and the spirit rested upon them; and they were of them that were written, but went not out unto the tabernacle: and they prophesied in the camp.
27 And there ran a young man, and told Moses, and said, Eldad and Medad do prophesy in the camp.
28 And Joshua the son of Nun, the servant of Moses, one of his young men, answered and said, My lord Moses, forbid them.
29 And Moses said unto him, Enviest thou for my sake? would God that all the LORD's people were prophets, and that the LORD would put his spirit upon them!"  (Old Testament | Numbers 11:26 - 29)

In this case, I believe "prophets" were leaders, teaching by the power of the Holy Ghost.  Would to God that all leaders would worthy and have the Spirit of the Lord upon them.