Mother
In general, mothers in the Bible represent the Lord's church on earth. In some cases "mother" more specifically refers to the truth of the church, the true teachings the church has about the Lord and about life. This makes sense if you think about it. Mothers are the vehicles through which new people are created; the church (in a broad sense) is the vehicle through which new ideas about the Lord and new good actions are created. And just as a mother is filled with love -- for her children and husband -- so also is the church filled with love, both for its ideas and uses and also for the Lord.
Arcana Coelestia #5686
5686. 'His brother, his mother's son' means the internal born from the natural as its mother. This is clear from the representation of Benjamin, to whom 'brother' and 'mother's son' refer here, as the internal, dealt with in 5469. And since this is the intermediary it comes into being from the celestial of the spiritual, represented by 'Joseph', as its father, and from the natural as its mother; for it must have its beginning in both these if it is to serve as an intermediary. So this is what is meant by the internal born from the natural as its mother. Also because the celestial of the spiritual, which is 'Joseph', had come into being in a similar way from the natural as its mother, but from the Divine as its father, 'Benjamin' is therefore called, as he was in actual fact by birth, 'his brother, his mother's son'; and in what immediately follows he is also addressed as 'son'. The name 'brother' is used by the Lord, who is meant here in the highest sense by 'Joseph', to refer to everyone who has any good of charity which he has received from the Lord. He is also referred to as 'his mother's son', but in this case 'mother' is used to mean the Church.