" And the angel said unto her, Fear not, Mary: for thou hast found favour with God. And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS. He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end. The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God. For with God nothing shall be impossible. "
Luke 1:30-33, 35, 37
Between these lines of scripture are the outlines of Mary's reactions to what Gabriel is saying to her. It says she was troubled and wondered what the greeting meant. She also questioned how she was to be with child, since she had not been with a man. I'm sure there was panic and fear rising up in her as she wondered how - and why - Jehovah God had chosen her to be the incubator of His flesh being. Yet, Gabriel ended his revelations to her with the perfect reassurance: Nothing is impossible with God. I am sure that at that moment peace washed over and she felt calmed.
Whatever seemingly impossible mountain you are facing, keep in mind that with God NOTHING is impossible. All you have to do is believe, only believe. Faith in God is what moves those mountains!