Almost everyone talks about faith because almost everyone has faith in something.
But faith is only as good as its object. It is important to recognize that we are not saved from condemnation by having faith in faith. Paul commended the Colossians for their "faith in Christ Jesus" (Col. 1:4).
So it is not sufficient to tell a person, "Just believe." The question is, Believe what? The message of the Gospel is not to believe in yourself, in church or in doctrine but in the Lord Jesus Christ.
This implies believing in all that Christ did for us when He died on the cross in our place. It recognizes that we are sinful human beings who deserve condemnation, or else it would never have been necessary for Christ to die.
It means we recognize that Christ is our only hope because if we could have been saved by some other means, Christ would not have had to die (see Gal. 2:21).
Having faith in Jesus Christ implies we have placed our confidence entirely in His finished work on the cross, recognizing that He forgives our sins and gives us eternal life.
One can summarize saving faith as a commitment to Jesus Christ, who is our life and Lord. Faith in Jesus Christ as our Lord is also necessary for growth in our Christian walk.
"And they said, Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house" (Acts 16:31).