What is the faith that will bring us salvation?

What is the faith that will bring us salvation? Is it enough to believe in Jesus Christ, the Son of God?

St John Chrysostom writes

He that believes in the Son has everlasting life." Is it enough, then, to believe in the Son,' someone will say, 'in order to have everlasting life?' By no means! Listen to Christ declare this himself when he says, 'Not everyone who says to me, "Lord! Lord!" shall enter into the kingdom of heaven'; and the blasphemy against the Spirit is alone sufficient to cast him into hell. But why should I speak of a part of our teaching? For if a man believe rightly in the Father and in the Son and in the Holy Spirit, but does not live rightly, his faith will avail him nothing toward salvation (Homilies on the Gospel of John 31:1[circa A.D. 391]).

Jesus himself tells us that mere belief is not sufficient. The Lord Himself said, 

“Not everyone who says to Me, `Lord, Lord,' shall enter the kingdom of heaven” (Matt 7:21). The Lord continues “Many will say to Me in that day, `Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?' And then I will declare to them, `I never knew you; depart from Me, you who practice lawlessness!'  (Matt.7:22-23).

Faith is not simply a belief but also a life. You can test it by its fruits in your life... as the Lord said

 “You will know them by their fruits….every good tree bears good fruit, but a bad tree bears bad fruit. Therefore by their fruits you will know them” (Matt. 7:16-20).

John the evangelist teaches us

 “Now by this we know that we know Him” how? “If we keep His commandments. He who says, "I know Him," and does not keep His commandments, is a liar, and the truth is not in him ” (1 John 2:3-4). 

Faith is tested through a life of obedience to God's commandments, and he who does not have this obedience is not considered a believer of Truth, and can not claim to know God.