The Bible teaches that there are different degrees of faith. These include faith that is:
For a faith to be a saving faith, it must be strong enough to cause one to obey God for obedience is essential to salvation (Heb. 5:9; 2 Thes. 1:7-9). A mere conviction is not enough to save. James 2:19 says, "You believe that there is one God. You do well. Even the demons believe -- and tremble!" Though demons believe, no one would argue that they are saved. John 12:42 states that many of the rulers of the Jews believed in Jesus but they would not confess that belief because they did not want to be expelled from the synagogue. Would anyone aver that they were saved?
Faith must include obedience in order for it to be a saving faith. As a matter of fact, in every reference to "faith" as a means of salvation, the saving faith is an obedient faith. John 3:16 is often cited by those who say that faith is all one needs to be saved. But compare John 3:16 with John 3:36. In verse 36, the word "believe" occurs twice in the KJV but the original Greek text had two different words. The first "believe" is from the Greek word pisteuo, the latter from the Greek peitho. Pisteuo means "to be persuaded, to place confidence in, to trust" (Vine's Expository Dictionary of NT Words), while peitho is to "obey" (Vine). The latter implies the obedience that is produced by the former. More than simple belief, conviction, is necessary for salvation.
Salvation is by faith (Rom. 5:1; Eph. 2:8-9) but not by "faith only." Faith alone is dead while an obedient faith is living (Jas. 2:17, 20, 26). Faith alone is imperfect while an obedient faith is perfect (Jas. 2:22). Faith alone does not save or justify but an obedient faith saves or justifies (Jas. 2:14, 24). Faith alone characterizes the demons (Jas. 2:19-20) while an obedient faith characterized Abraham (Jas. 2:21-23; Heb. 11:8-10). Faith alone characterized many of the Jewish rulers (John 12:42-43) while an obedient faith characterized Noah (Heb. 11:7).
The only occasion in which the phrase "faith only" is used in Scripture is to show that it, by itself, justifies no one (Jas. 2:24).
A saving faith is one that is strong enough to cause the believer to obey the gospel, God's power unto salvation (Rom. 1:16).