Luke 1:34 to 1:37 (KJV)
Then said Mary unto the angel, How shall this be, seeing I know not a man?
And the angel answered and said unto her, 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.
And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren.
For with God nothing shall be impossible.