In the Old covenant God's revelation comes through men, Adam, Noah, Abraham, Isaac, Jacob, Moses and the Prophets and they express the reality of God in masculine terms such as Lord, King, Judge, Shepherd and Lover. It is written that the Word of the Lord came to the Prophets and they in turn use the expression"Thus says the LORD ....". They never said, "Thus says the LADY...." In a few instances God is called father, "Yet, LORD, you are our father; we are the clay and you our potter: we are all the work of your hand." (Is 64:7) And in even fewer instances he is compared to a mother's care, "As a mother comforts her child, so will I comfort you; and you will be comforted over Jerusalem." (Is 66:13) "Roland Frye has amply demonstrated, the few instances of feminine imagery for God in the Bible all take the form of a simile and not of a metaphor, and that distinction is crucial. A simile compares one aspect of something to another. For example, in Isaiah 42:14, God will cry out like a woman in travail, but only his crying out is being referred to; he is not being identified as a whole with the figure of a woman in childbirth. In metaphors, on the other hand, identity between the subject and the thing compared to it is assumed. God is Father, or Jesus is the Good Shepherd, or God is King." (Exchanging God for No Gods: A Discussion of Female Language for God By Elizabeth Achtemeier)
God is never given the name Mother in the Old Covenant. The Songs of Song is a love poem between man and woman, "Like an apple tree among the trees of the woods, so is my lover among men. In his shadow I delight to sit, and his fruit is sweet to my taste." (Song of Songs, 2:3)"While the lovers in the Song are clearly human figures, both Jewish and Christian traditions across the centuries have adopted allegorical interpretations. The Song is seen as a beautiful picture of the ideal Israel, the chosen people whom the Lord leads by degrees to a greater understanding and closer union in the bond of perfect love." (Commentary in Catholic Bible) The covenant between God and Israel is always expressed in masculine terms.
God is a spirit who created man and woman. They reflection both masculinity and femininity in God. So, why did he reveal Himself in masculine terms?
Some would say that the masculine language of God was the creation of the Jewish patriarchal culture. But this patriarchal culture was dictated by God. Had the Jews being left to themselves they would have worshipped both male and female deities. "Israel's idea of God's fatherhood bucked the common trend of the ancient world. Hence, it could not have been an Israelite invention, but rather the result of a long history of living under the revelation of God. "Website: Why We Call God 'Father' by Jeremy Weber an Ted Olsen" In the Catechism of the Catholic Church we read, "In Israel, God is called "Father" inasmuch as he is Creator of the world. Even more, God is Father because of the covenant and the gift of the law to Israel, "his first-born son". (CCC #238)
Further, God the Father looked forward to the Incarnation of his only Son in Mary's womb. If we conceive God as Mother having incarnated a daughter, we would have had "Divine Daughter" and a "Holy Mother" leaving man out from the plan of Redemption. And Again, if God the Father had sent a daughter to be incarnated, the result would have been the same. If we were to call God "Mother" and Mary "Mother of God", this would be the beginning of a great confusion.
In Conclusion, "The Bible uses masculine language for God because that is the language with which God revealed himself. ... It claims no knowledge of God beyond the knowledge God has given of himself though his words and deeds in the histories of Israel and Jesus Christ and his church." (Elizabeth Achtemeir,1992:5).