Ephesians 2:8-9 -- "God saved you by his grace when you believed. And you can’t take credit for this; it is a gift from God.9 Salvation is not a reward for the good things we have done, so none of us can boast about it."
However, when we believe in Jesus by faith, we allow Him to enter our hearts and change us. We are no longer the same person as we once was. Thus we do not act in the same selfish ways.
Of course, this is a process. You do not change overnight, but you are always working to be better, to be more like Christ everyday.
Faith alone allows you to enter heaven; however, "faith is dead without good works" (James 2:26). It is because of our faith and Christ in our life that makes us want to love on others and help other when we can. Our good works are merely an extension of God's love for us. He loves us so we can reach out and love others.
By faith I believe you are who you say you are and you will do what you say you will do. Help me to complete good works as an extension of my faith, not for personal benefit, but so I can show others the love that you show me.