“Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new” 2 Corinthians 5:17
Christianity isn’t ‘foundationally’ about what you do but about who you are.
‘Doing good’ isn’t what makes you a Christian. You are a Christian because you believe in Jesus, who in response to your faith, has made you a new man with new desires by His Spirit.
In other words, instead of the popular notion: “I must do good to be a Christian”, the truth is, I can do good because I am a Christian.
For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.
Christianity isn’t a lifestyle, but a life that has a lifestyle. It is a new nature you receive when the Holy Ghost comes to dwell in you.
However, when you receive the life of God, your lifestyle is influenced for the better. A righteous lifestyle is the result, not the prerequisite for being a Christian.
For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:  Not of works, lest any man should boast.
Your lifestyle proves that you have received the life of God, but it isn’t the life of God in itself.
Friend, there is a huge difference between striving for righteousness ‘to be’ (or keep being) a child of God and striving for righteousness ‘because’ you are a child of God.
Recognizing who you are in Christ empowers you to effortlessly produce fruits of righteousness, consistent with the nature of righteousness that you have received as a gift.
I have the life of God in me. I am a new creature in Christ. God works in me to do His good pleasure. Hallelujah!