This is the glory of faith, simply not to know: not to know where you are going, not to know what you are doing, not to know what you must suffer, and with sense and intellect, virtue and will, all alike made captive, to follow the naked voice of God … Abraham with his obedience of faith shows the highest example of the evangelical life, because he left all and followed the Lord, preferring the word of God to everything else and loving it above all things; of his own free will a pilgrim, and subject to the perils of life and death every hour of the day and night.
(Martin Luther)
"Therefore the Lord himself will give you a sign: The virgin will be with child and will give birth to a son, and you will call him Immanuel."
Isaiah 7: 14