Is there any mention about God the Mother in the Bible? I have to prepare for a group who is going to convince me from the Bible that it does teach about God the Mother.
I'm assuming you have run into members of World Mission Society Church of God. This is a group that started in South Korea in 1964. They believe their founder, Ahn Sahng-hong, who died in 1985, is the Christ and his wife, Jang Gil-ja, who is still alive, is God the Mother.
They justify these heresies by pulling verses out of context and reassigning meaning of basic terms. They start with "So God created man in his own image, in the image of God created he him; male and female created he them" (Genesis 1:27). The argument is since male and female were created in the image of God; therefore God is composed of both male and female members. Of course, what the Bible actually teaches is that God is a Spirit. "God is spirit, and those who worship Him must worship in spirit and truth" (John 4:24). Genesis 1:27 informs us that humans (male and female) have spirits like God. It does not say that God has physical attributes.
They also take the verses where Jesus says, for instance, "For this is the will of My Father, that everyone who beholds the Son and believes in Him will have eternal life, and I Myself will raise him up on the last day" (John 6:40). They claim that this must be done by God the Mother because mothers raise children and give life. But take note that the later claim is made without evidence. It also ignores the fact that Jesus said that he would raise those who believe in him and give them eternal life.
Then they take the verses that talking about the bride of Christ and claim that these refer to God the Mother. Again, this is done by claim and not proof. It ignores the fact that bride of Christ is the church. "Husbands, love your wives, just as Christ also loved the church and gave Himself up for her, so that He might sanctify her, having cleansed her by the washing of water with the word, that He might present to Himself the church in all her glory, having no spot or wrinkle or any such thing; but that she would be holy and blameless" (Ephesians 5:25-27).
They also quote, "But the Jerusalem above is free; she is our mother" (Galatians 4:26). But they ignore that this verse is talking about an allegory. "This is allegorically speaking, for these women are two covenants" (Galatians 4:24). We are talking about the Old Testament versus the New Testament, not deities.
What you will find is that this group has built a religion around two dynamic individuals. They then pulled phrases from the Bible to claim what they already believe. Nothing is truly proven.