The great sea was obviously the ocean, whether the Atlantic or the Pacific ocean is not known. There are theories regarding which ocean, but they will not be discussed in this work.
Many readers draw the conclusion that the brother of Jared did not pray for the four years that they dwelt in tents upon the seashore. However, there is a big difference between saying your prayers and calling upon the name of the Lord (v. 14). The Jaredites had been led continually by the hand of the Lord as they traveled from the valley of Nimrod to the place they called Moriancumr. Certainly the brother of Jared, as their prophet-leader, had prayed for guidance and received answers to his prayers as they journeyed. Although he must have prayed daily, and probably several times a day, his prayers were probably in gratitude for the direction they had been given. The group had probably temporally lost sight of their objective, the land of promise. How often do we get part way on our earthly journey and lose sight of our eternal goals? While nothing succeeds like success, sometimes success stifles our progress and we settle for partial blessings. Faith unto salvation “is an actual knowledge that the course of life which one is pursuing is according to [God’s] will” (Lectures on Faith, 3:5).
The Lord took this opportunity to teach the Jaredites a lesson. He told them the Spirit will not always strive with man (v. 15). As used here, it suggests that the Spirit had led them before, but their past experiences would not suffice for their future travels. After one has entered into the way, he must press forward and the Holy Ghost “will show unto you all things that ye shall do” (2 Nephi 32:5).