If we want to know what Christ himself said about a matter, we should look first at the Doctrine and Covenants, and afterwards at the Book of Mormon and the New Testament. The amount of Christ's actual words that we find in the Doctrine and Covenants is vastly more than what we find in either of the other two books. We also shouldn't neglect the Pearl of Great Price and the Old Testament, for god is the same yesterday, today, and forever. If we think that Christ in the New Testament acts differently that he did in the other scriptures, we need to pause and reflect on whether that really makes sense.
In the new testament, we frequently read about Christ's dealings with those that have faith to be healed, or are following him around, wishing to hear his teachings.
By contrast, in the old testament we read of his dealings with ancient Israel who was not righteous enough to generally be granted the Aaronic priesthood, and frequently fell to worshipping Idol gods.
Our problem is not that Christ is not consistent across the different books, it is that we fail to understand something Joseph Smith perfectly explained.
Joseph Smith taught: Our heavenly Father is more liberal in His views, and boundless in His mercies and blessings, than we are ready to believe or receive; and, at the same time, is more terrible to the workers of iniquity, more awful in the executions of His punishments, and more ready to detect every false way, than we are apt to suppose Him to be.