[annalex]

John 6:28-29

Yes, of course. both faith and good works are necessary. This passage says that they go together: if you believe you will do good works, and if you do good works you believe. You are not saved by faith alone, nor by works alone.

[CynicalBear]

If you have faith and believe, you have the Holy Spirit within you. Scripture tells us of many who were saved and indwelt with the Holy Spirit immediately. It is that which inspires the good works. If you have the Holy Spirit within you it is indicative of having been saved because the Holy Spirit would not indwell an unsaved person. No one with the indwelt Holy Spirit would be able to sin without feeling the guilt. If you blaspheme the Holy Spirit He leaves you and will not come back. Thus the deadly sin of blaspheming the Holy Spirit.