A new poster to the “Islam and Christianity Debate Group” posted a long analysis of “The Difference between Jesus Christ’s Concept of Salvation and Paul of Tarsus’s Concept of the Salvation” (which I cite in part): The Muslim Challenge: Paul misled the way to salvation by excluding one of the essential elements, that is observance of the Law of Commandments. He advised only the lip service, escaping from the responsibility to keep the commandments. He wronged the concept of righteousness and faith, and misrepresented the judgement of God. To become righteous, and to achieve salvation, faith alone, is not sufficient, obedience to God's commands is a must, but according to Paul he has a different and weird concept : a-" For we come to the conclusion that a man is justified by faith without the works of the Law." (Romans 3:28) b-" It is the message of faith, which we preach, that if you confess with your lips the Lord Jesus and believe in your heart that God raised Him from the dead, you will be saved. For with the heart one believes so that he is made righteous and with the mouth confession is made for salvation." (Romans 10:9) Although Jesus {P.B.u.h.} taught his followers that anyone who attains salvation, must have faith in God, and at the same time must obey the revelations of God. It is contrary to every human intellect, that the salvation can be obtained by faith, leaving aside the practical obedience to God. However, we read in (Matthew 5:19) "Whoever, therefore, abolishes the least significant of these commands and so teaches the people , he shall be of least significance in the Kingdom of heaven; but whoever shall observe and teach them shall be prominent in the Kingdom of heaven.” And in (Matthew 19:17) "If you wish to enter into life keep the commandments."   My Answer: In my careful and considered judgement, your understanding of the connection between Jesus and Paul is mistaken. First, it is recorded in the Bible that Jesus Himself specially chose the Apostle Paul, as recorded in Acts 9:15,

Act 9:15  But the Lord said unto him, Go thy way: for he is a chosen vessel unto me, to bear my name before the Gentiles, and kings, and the children of Israel:

Second, I believe you may not properly understand the relationship between Law and Grace. Jesus fulfilled the requirements of the Law. Jesus brought grace as the means of salvation, grace which is freely available to all who truly believe in our Lord Jesus Christ:

John 1:17  For the law was given by Moses, but grace and truth came by Jesus Christ.

John 3:16  For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.

John 5:24  Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.

John 14:6  Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.

Third, it is clear from the written record that Paul received his message or doctrine by direct revelation from our Lord Jesus Christ Himself:

Gal 1:11  But I certify you, brethren, that the gospel which was preached of me is not after man.

Gal 1:12  For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ.

Gal 1:11 My friends, I want you to know that no one made up the message I preach.

Gal 1:12 It wasn't given or taught to me by some mere human. My message came directly from Jesus Christ when he appeared to me. (CEV)

1Co 14:37  If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I write unto you are the commandments of the Lord.

Fourth, the divine inspiration of what Paul wrote was acknowledged by Peter, who speaks of Paul's letters as Scripture:

2Pe 3:15  And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you;

2Pe 3:16  As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.