"The more sure word of prophecy means a man's knowing that he is sealed up unto eternal life, by revelation and the spirit of prophecy, through the power of the Holy Priesthood."
The following quote from Joseph Smith sheds further light on this subject.
"After a person has faith in Christ, repents of his sins, and is baptized for the remission of his sins and receives the Holy Ghost, (by the laying on of hands)...then let him continue to humble himself before God, hungering and thirsting after righteousness, and living by every word of God, and the Lord will soon say unto him, Son, thou shall be exalted. When the Lord has thoroughly proved him, and finds that the man is determined to serve Him at all hazards, then the man will find his calling and his election made sure, then it will be his privilege to receive the other Comforter, which the Lord hath promised the Saint, as is recorded in the testimony of St. John." (Teachings of the Prophet Joseph Smith, p. 150.)
I didn't come to realize what this verse implied until after my marriage. I was young and still very foolish. I prayed that I would receive this great blessing, and let me tell you all hell broke loose in my life. It was to the point I cried, enough I don't want it. I left the matter alone. Years past and I thought I was spiritually stronger and more prepared and I asked for this again, and all hell broke loose in my life. I left the matter alone. Years go by and I think I'm ready. I'm stronger and can weather whatever test he gives me now. I ask again and all hell breaks loose, but this time I realized the problem was me.
It was time to get really real with myself. I was asking for this great blessing because I actually didn't believe. I wanted such a witness so I would see with my own eyes that Jesus was really real. I was prideful and asking for such a thing was the greatest example of my offense. I repented and sought only to learn of Him. I began to read and really ponder over the scriptures and tried to be faithful to what I was learning. I found out how imperfect I really am, how much I need his atonement. What a great price he has paid for me. I realized how weak I am, and I would never have found him if I tried to carry my burdens on my own. It made perfect sense why all hell had broke loose in my life earlier. I had not learned to walk beside him, and let him carry me. Today I know my Savior and seeing him in the flesh or not will make no difference. He is so very real to me.