Mother goddes

This appears to be a reference to the World Mission Society Church of God, a group founded in South Korea that teaches God the Mother alongside God the Father — a belief entirely incompatible with Catholic teaching.

On the Trinity: The Church definitively teaches that God is one divine essence in three Persons: Father, Son, and Holy Spirit. There is no "Mother God" in the Trinity. The Catechism states: "The Trinity is One. We do not confess three Gods, but one God in three persons" (CCC §253). The Council of Constantinople (381 AD) affirmed the Nicene Creed, which professes faith in the Father, the Son, and the Holy Spirit — with no fourth person.

On Sabbath observance: While Saturday was the Jewish Sabbath, Christians from apostolic times have gathered on Sunday, the Lord's Day, to celebrate the Resurrection. "Sunday is the day on which the paschal mystery is celebrated in light of the apostolic tradition and is to be observed as the foremost holy day of obligation" (CCC §2177; cf. Acts 20:7, 1 Cor 16:2).

Pastoral note: Groups like this often use Christian terminology while teaching something fundamentally different. The Church urges discernment: "There are many 'spirits' in the world, and we must test them to see if they are from God" (cf. 1 John 4:1). If you encounter members of this group, approach with charity but firmness in the truth of the apostolic faith.