There is a point in the progress of the soul where the spirit is sufficiently with one that the distinction between righteousness and sin becomes not only apparent, but that sin itself is recognized and abhorred. Thus Jacob notes that he has come to the point where his perception of the effects of sin is sufficiently great that he is repelled by it. Thus also, the people of Benjamin will also receive a sufficient spiritual witness that they too find themselves in the same condition:
Mosiah 5:2
2 And they all cried with one voice, saying: Yea, we believe all the words which thou hast spoken unto us; and also, we know of their surety and truth, because of the Spirit of the Lord Omnipotent, which has wrought a mighty change in us, or in our hearts, that we have no more disposition to do evil, but to do good continually.
Of course this contrasts with the all too human trait of being attracted to certain sins. There are times in our natural state when not only do we not make such immediate and clear distinctions between righteousness and sin, but we actually seem to favor certain sins.
These are sins that I would term "favorite sins." These are things that we love so much that we want to keep doing them in spite of understanding that they are sins, or at best, marginal sins. Most people seem to have one or two, and they are easily located by finding the aspect about our lives about which we make the greatest number of excuses. The very thing that compels us to excuse our action is our recognition that it is probably not correct. The fact that we want to do it, however, compels us to assuage our conscience by fabricating multiple excuses that we can use to defend our position from the necessity of repentance.
For Jacob, he had no need of such personal defensive measures, for he had come to the point where his desire was to righteousness. For the people of Benjamin also, the strong presence of the spirit had the same effect. When we achieve that same touch of the spirit, we can also see past the fabricated excuses, and begin the process of repentance, and true happiness rather than layered excuses.