"By their fruit you will recognize them. Do people pick grapes from thorn bushes, or figs from thistles? Likewise, every good tree bears good fruit, but a bad tree bears bad fruit."
Matthew 7:16-17
When you put your faith in Jesus, God essentially changes your nature from being a thornbush to a grapevine. If you keep producing thorns instead of fruit, then something's up.
What do I mean by thorns?
"Sexual immorality, impurity, and debauchery; idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions, and envy; drunkenness, orgies, and the like."
Galatians 5:19b-21a
What do I mean by fruit?
"Love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self control."
Galatians 5:22-23a
You cannot change your own nature through your actions. Deeds cannot save you. Paul was right when he said: "For it is by grace you are saved, through faith - and this is not from yourselves, it is the gift of God." [Ephesians 2:8]. But when God saves us, He remakes us, and consequently that changes our actions. Good works do not come before faith, rather they are a result of faith.
Before Paul got into clarifying that faith is what comes first, before James got into clarifying that works are not irrelevant, Jesus summed it up pretty nicely:
"By their fruit you will recognize them."
Matthew 7:20
Just because your deeds cannot save you doesn't mean they don't matter.