HOW CAN MAN RECEIVE THE GREAT GIFT OF SALVATION FROM SIN?

Only by obeying the Gospel of Jesus Christ; that is, by doing what He has commanded. There is no other way. St. Paul says of Christ:

"Being made perfect, he became the author of eternal salvation unto all them that obey him." (Hebrews 5: 9).

The Savior Himself says:

"Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my father which is in heaven." (Matthew 7: 21).

"If ye love me, keep my commandments." (John 14: 15).

"He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father, and I will love him, and will manifest myself to him." (John 14: 21).