JST Matthew 5
21 Whosoever, therefore, shall break one of these least commandments, and shall teach men so to do, he shall in no wise be saved in the kingdom of heaven; but whosoever shall do and teach these commandments of the law until it be fulfilled, the same shall be called great, and shall be saved in the kingdom of heaven.
22 For I say unto you, except your righteousness shall exceed that of the Scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.
Joseph taught that to be righteous meant to be just and merciful. To be just means doing what has been asked of one, or what one has agreed to do. To be merciful means to have no malice even towards one's enemies, but to be of a mind to let them go even when they are in your power after their having come upon you, and perhaps blessing them in the bargain. Joseph also taught that becoming righteous comes about by obedience to God's commandments. The Scribes and Pharisees were not keeping the law and commndments, and lacked mercy.
JST Matthew 7
1 Now these are the words which Jesus taught his disciples that they should say unto the people.
2 Judge not unrighteously, that ye be not judged; but judge righteous judgment.
3 For with what judgment ye shall judge, ye shall be judged; and with what measure ye mete, it shall be measured to you again.
4 And again, ye shall say unto them, Why is it that thou beholdest the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?
5 Or how wilt thou say to thy brother, Let me pull out the mote out of thine eye; and canst not behold a beam in thine own eye?
6 And Jesus said unto his disciples, Beholdest thou the Scribes, and the Pharisees, and the Priests, and the Levites? They teach in their synagogues, but do not observe the law, nor the commandments; and all have gone out of the way, and are under sin.
7 Go thou and say unto them, Why teach ye men the law and the commandments, when ye yourselves are the children of corruption?
8 Say unto them, Ye hypocrites, first cast out the beam out of thine own eye; and then shalt thou see clearly to cast out the mote out of thy brother's eye.
A hypocrite is an actor, one who pretends to be what he is not.
Notice Jesus did not instruct the disciples to challenge the authority of the Scribes, Pharisees, Priests, and Levites. The subjects of "priesthood" and "keys" and "authority" seem not to have been a consideration - even though by this time John, the Baptist, had "wrested the keys" and "overthrown the kingdom of the Jews." Jesus's complaint was that the teachers were not observing to keep the law nor the commandments. We know already they had long perverted the ways of the Lord, as John had come to make straight his paths, therefore whatever they were teaching was contrary to the law and the commandments. In other words, the situation of the teachers of the Jews was similar in most respects to that of the priests of King Noah to whom Abinadi was sent.
Remember also that Jesus never did get formally excommunicated - put out of the synagogue. Anyone can get themselves tossed - and several have gotten themselves tossed - by asserting the leadership lacks priesthood, authority, keys, or whatever, and that the historical narrative which buttresses their claims is false. Here's what Jesus said to do instead.
9 Go ye into the world, saying unto all, Repent, for the kingdom of heaven has come nigh unto you.
10 And the mysteries of the kingdom ye shall keep within yourselves; for it is not meet to give that which is holy unto the dogs; neither cast ye your pearls unto swine, lest they trample them under their feet.
The dogs, in this context, are those who do not recognize the Lord's voice in the words of his servants, who start barking where the law and commandments contradict the teachings of the leadership, preferring the leadership's teachings. The swine are the contentious who argue every little point and accuse.
11 For the world cannot receive that which ye yourselves, are not able to bear; wherefore ye shall not give your pearls unto them, lest they turn again and rend you.
The pearls, or mysteries, being revelations of the operations of God's kingdom, apparently - those things Jesus taught in parables to hide them from the unbelievers.
12 Say unto them, Ask of God; ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you.
13 For every one that asketh, receiveth; and he that seeketh, findeth; and unto him that knocketh, it shall be opened.
Teach them that God answers prayers. Sometimes, we must weary him (Luke 18:1-6).
14 And then said his disciples unto him, they will say unto us, We ourselves are righteous, and need not that any man should teach us. God, we know, heard Moses and some of the prophets; but us he will not hear.
15 And they will say, We have the law for our salvation, and that is sufficient for us.
16 Then Jesus answered, and said unto his disciples, thus shall ye say unto them,
17 What man among you, having a son, and he shall be standing out, and shall say, Father, open thy house that I may come in and sup with thee, will not say, Come in, my son; for mine is thine, and thine is mine?
18 Or what man is there among you, who, if his son ask bread, will give him a stone?
19 Or if he ask a fish, will he give him a serpent?
20 If ye then, being evil, know how to give good gifts unto your children, how much more shall your Father who is in heaven give good things to them that ask him?
God will answer the sincere seeker.
21 Therefore, all things whatsoever ye would that men should do to you, do ye even so to them; for this is the law and the prophets.
Every last thing you wish people would do to you, do to others. This is the meaning of the law, and of the teachings of the prophets. This short, simple explanation of the entirety of the law of God cuts through all the accretions of men, the claptrap and clutter surrounding the law and the commandments.
As an aside, you can't escape the requirements of this, the Golden Rule, by appealing to the so-called "Greatest Commandments." If you love your neighbor as yourself, then if you would do a thing for yourself, you had ought to do it for your neighbor. Let that thought sink in.
22 Repent, therefore, and enter ye in at the strait gate; for wide is the gate, and broad is the way that leadeth to destruction, and many there be who go in thereat.
23 Because strait is the gate, and narrow is the way that leadeth unto life, and few there be that find it.
The strait gate is repentance and baptism by water, after which cometh the baptism of fire and of the Holy Ghost. The narrow way that leadeth unto life is this, the Sermon on the Mount / Plain / Bountiful. Few find it because they fear the obvious consequences in this world of obedience to Jesus's sayings and commandments, therefore they disbelieve him and do not obey, and they teach others to disobey, saying things like "you're a simplistic fool if you give to everyone who asks you to!"
Hence this: "Whosoever, therefore, shall break one of these least commandments, and shall teach men so to do, he shall in no wise be saved in the kingdom of heaven; but whosoever shall do and teach these commandments of the law until it be fulfilled, the same shall be called great, and shall be saved in the kingdom of heaven."
The purpose of a priest is to teach the law and the commandments, remembering they are not his, but his who sent him.
24 And, again, beware of false prophets, who come to you in sheep's clothing; but inwardly they are ravening wolves.
25 Ye shall know them by their fruits; for do men gather grapes of thorns, or figs of thistles?
26 Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
27 A good tree cannot bring forth evil fruit; neither can a corrupt tree bring forth good fruit.
28 Every tree that bringeth not forth good fruit, is hewn down, and cast into the fire.
29 Wherefore by their fruits ye shall know them.
Very simply: do they keep the commandments and teach them, building up others, or do they instead break them and contend, seeking to aggrandize themselves?
30 Verily I say unto you, it is not every one that saith unto me, Lord, Lord, that shall enter unto the kingdom of heaven; but he that doeth the will of my Father who is in heaven.
31 For the day soon cometh, that men shall come before me to judgment, to be judged according to their works.
32 And many will say unto me in that day, Lord, Lord, have we not prophesied in thy name; and in thy name cast out devils; and in thy name done many wonderful works?
33 And then will I say, Ye never knew me; depart from me ye that work iniquity.
Those who actually keep the commandments will know him; those who say and do not will not.
34 Therefore, whosoever heareth these sayings of mine and doeth them, I will liken him unto a wise man, who built his house upon a rock, and the rains descended, and the floods came, and the winds blew, and beat upon that house, and it fell not; for it was founded upon a rock.
35 And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, who built his house upon the sand; and the rains descended, and the floods came, and the winds blew, and beat upon that house, and it fell; and great was the fall of it.
If you hear these sayings of his - the Sermon on the Mount / Plain / Bountiful - and do them, you will be founded upon a rock. If you hear these sayings of his and don't do them, you will fall.
36 And it came to pass when Jesus had ended these sayings with his disciples, the people were astonished at his doctrine;
37 For he taught them as one having authority from God, and not as having authority from the Scribes.
Jesus seems not to care so much what we believe so long as we believe on - have full faith and trust in - him and keep his commandments. The rest is taught directly from heaven.