VATICAN CITY (CNS) — Being Christian is humbly serving others, not applying “makeup” to your soul to make it prettier, Pope Francis said.

“To be Christian is to do what Jesus did — serve,” he said in a homily April 30 during Mass in the chapel of his residence, the Domus Sanctae Marthae.

Thinking about oneself and being self-centered “is a sin, it’s a habit we have to break,” he said, according to Vatican Radio. Just ask for forgiveness and pray “that the Lord convert us,” he added.

“To be Christian isn’t about appearances or social conduct, it isn’t putting a bit of makeup on the soul so that it’s a little more beautiful,” he said.

A Christian serves others and people should ask themselves, “Do I have others serve me, do I take advantage of others, the community, the parish, my family, my friends or do I serve, am I at the service” of others?” he said.

Being a Christian is also about recognizing that one is part of an entire people on a journey with God, not an individual whose spirituality is concocted in an abstract or controlled environment, like a laboratory, he said.

God has made his people “walk for centuries in order to reach” maturity, “the fullness of time,” he said.

“How many sinners, how many offenses” along this journey, this long history of sin and grace, he said. “Our history must take on saints and sinners. It is my personal history, everyone’s, it must take on our sin.”

God’s grace is always there, he said, because he is “with us, accompanying us in (our) sin in order to forgive and accompanying us in grace. There is no Christian identity without history.”