Nephi saw the Lord would be rejected as a stumbling block. He was to be an offense to His contemporary religious leaders. There could be no greater stumbling block to His people than a Lord who suffers official rejection by the leadership, and ultimate crucifixion at the religious leaders' instigation. This was what Nephi saw, the events to which he testified, and what Isaiah's words about the Messiah confirm. To those who were insensitive to the Spirit, Christ looked wrong, associated with the wrong people, failed to hold appropriate priestly office and station, and was vulgar. He came just as He should have come. It required those who would follow Him to look with the eyes of faith, listen with the heart, and be touched by the power of His words. If they only wanted to accept bona fide official channels established under the Mosaic Law, they would never recognize Him as the promised Messiah.
The test is always the same for each of us. We all are required to accept truth from unlikely sources. We all are required to see the Lord's hand in our lives. It will be inconvenient, even homely, at times. Not at all what we would expect, coming from where we were not looking, and asking us to do things which are difficult. Either we respond and follow Him, or we do not, and find Him a "stumbling block" and "rock of offense." He doesn't change, nor does His test for us change. He will always be the inconvenient Messiah, requiring faith to follow Him.