Todays is the memorial of St. John the Apostle. The Office of the Reading, from the Liturgy of the Hours is taken from 1 John.
This verse touched me and is relevant to this topic.
My children, I am writing this to you so that you may not commit sin. But if anyone does sin, we have an Advocate with the Father, Jesus Christ the righteous one.
He is expiation for our sins, and not for our sins only but for those of the whole world.
Whether a person knows Christ or not, He is still the expiation for their sins.
St. Augustine’s writing is also part of the OR today. If you have it, its well worth reading.