We must note the clear antithesis between the law and the gospel. The distinction between the two is important because, as Luther indicates, it contains the substance of all Christian doctrine. "By the law," says he, "nothing else is meant than God's word and command, directing what to do and what to leave undone, and requiring of us obedience of works. But the gospel is such doctrine of the word of God that neither requires our works nor commands us to do anything, but announces the offered grace of the forgiveness of sin and eternal salvation. Here we do nothing, but only receive what is offered through the word." The gospel, then, is the message of God, the teaching of Christianity, the redemption in and by Jesus Christ, the only begotten Son of God, offered to all mankind. And as the gospel is bound up in the life of Christ, His biography and the record of His works, and the proclamation of what He has to offer, are all gathered into this single word, of which no better definition can be given than that of Melanchthon: "The gospel is the gratuitous promise of the remission of sins for Christ's sake." To hold tenaciously that in this gospel we have a supernatural revelation is in perfect consistency with the spirit of scientific inquiry. The gospel, as the whole message and doctrine of salvation, and as chiefly efficacious for contrition, faith, justification, renewal and sanctification, deals with facts of revelation and experience.