Therefore it was made clearly manifest that salvation is in the Church, and of the Church, and is obtained only through the Church.
Mark E. Petersen, Salvation Comes through the Church, Ensign, July 1973
So lets look at what Br. Peterson's real intent was;
"When the Savior established his church during his mortal ministry, and as it was further developed by the twelve apostles of that day, one important fact became conspicuously clear, which is: that salvation comes through the Church.
It does not come through any separate organization or splinter group nor to any private party as an individual. It comes only through the Church itself as the Lord established it.
It was the Church that was organized for the perfecting of the Saints.
It was the Church that was given for the work of the ministry.
It was the Church that was provided to edify the body of Christ, as Paul explained to the Ephesians."
So Peterson was talking about the church established by Jesus Christ. We can argue over the meaning but in Matt 16 Jesus told Peter he was establishing a Church. In 1 Cor 3 Paul talk about the church, he says he plants while another increase.
10 According to the grace of God which is given unto me, as a wise masterbuilder, I have laid the foundation, and another buildeth thereon. But let every man take heed how he buildeth thereupon.
11 For other foundation can no man lay than that is laid, which is Jesus Christ.
His letter to the Ephesians is important because he establishes the authority of the Church.
Ch 2
19 Now therefore ye are no more strangers and foreigners, but fellowcitizens with the saints, and of the household of God;
20 And are built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief corner stone;
21 In whom all the building fitly framed together groweth unto an holy temple in the Lord:
Ch 3 He hopes the new gentile converts will come;
"to the love of Christ, which passeth knowledge, that ye might be filled with all the fulness of God/the Father.... Unto him be glory in the church by Christ Jesus throughout all ages, world without end. Amen.
In Chapter 4 he tells us
4 There is one body /church, and one Spirit, even as ye are called in one hope of your calling;
5 One Lord, one faith, one baptism,
6 One God and Father of all, who is above all, and through all, and in you all.
Paul during his journey meets some men who were baptized unto John the Baptist and he makes them get baptized all over again and this time in the name of the Father, the Son and the Holy Ghost. There is only one baptism. There is only one true Gospel.
Now he goes back to those apostles
11 And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers;
12 For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ:
By the 'edifying of the body of Christ' I don't think he means the body of the church but for the preparation of the sacrament.
1 Cor 10
16 The cup of blessing which we bless, is it not the communion of the blood of Christ? The bread which we break, is it not the communion of the body of Christ?
17 For we being many are one bread, and one body: for we are all partakers of that one bread.
It was the responsibility of the leaders of the Church Jesus established to do this for the body of the Church.
For how long?
13 Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ:
Why?
14 That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive;
He warned the leaders in the Church that different men/wolfs would stand up to lead the people astray. It was the responsibility of the leadership to keep the doctrines pure.
15 But speaking the truth in love, may grow up into him in all things, which is the head, even Christ:
16 From whom the whole body fitly joined together and compacted by that which every joint supplieth, according to the effectual working in the measure of every part, maketh increase of the body unto the edifying of itself in love.
Jesus is both the cornerstone and the head of his Church.
Throughout Acts the body of the Church of Jesus Christ functions as intended. They met often to discus issues like circumcision and to call a new Apostle. As they traveled they established Churches and anointed Bishops, Elders etc.
But as time went on the false prophets began to arise as Jesus said they would and they taught a false gospel, which could not save anyone. Only within the Church established by Jesus Christ teaching the true gospel can salvation be found.
Br. Peterson makes that point;
"But there were men in the Lord’s own day who taught false doctrines and led the people into mistaken paths. These the Savior severely criticized, accusing them of apostasy from the very law of
Moses which they pretended to preach.
He said to them, “Did not Moses give you the law, and yet none of you keepeth the law?” (
John 7:19.)
And again he said, “… had ye believed Moses, ye would have believed me: for he wrote of me.” (
John 5:46.)
What a sad commentary! Had the people believed Moses, instead of the crafty false teachers of their day, they would have accepted Christ, because Moses wrote of Christ. And if they had accepted Jesus, they would have received salvation through his church.
But being blinded by false teachers, they rejected both Moses and Christ, and thus never joined the Lord’s church and hence did not receive the salvation which was available through it."
He goes on to name off some of the different groups that began to splinter off the original Church of Jesus Christ. They went into apostasy where there were no apostles, no prophets no authority to baptize or edify the body of Christ.
"Historians say that within one hundred years after Christ, as many as thirty splinter groups and separate denominations of Christians arose.
Further evidence of early apostasy in the Church is brought forcefully and particularly to our attention by the manner in which Paul wrote his first letter to the Corinthians.
In it he testified that there can be no divisions in Christ. Rather, he said, “… I beseech you, brethren, by the name of our Lord
Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment.” (
1 Cor. 1:10.)"
I think all of you would agree that salvation is not found in the Gnostics churches of those days and that was Br. Peterson's point.
He then turns his attention to the Latter Day Church and says the same thing is happening now. Ya all know there are various splinter groups within the umbrella called Mormonism.
"Salvation is not to be found in splinter groups today any more than it was to be found in the various denominations which polluted the teachings of Moses anciently or which, in the days of early Christianity, transgressed the laws, changed the ordinances, and broke the everlasting covenant."
I'm sure you look at us Mormons and want to say salvation is not found in your splinter group. Br Peterson's point is the same but standing on the other side of the argument.
I'm editing a little here, this is one of those examples where the speaker assume his audience already knows it's only through the merits of Christ we are saved as the Book of Mormon teaches.