It is narrated from Hazrat Bara bin Azib that when the Noble Prophet (peace and blessings be upon him) commanded us to dig the trench, a large rock appeared before us inside a mountain. Our pickaxes could not penetrate it. We complained about this to the Prophet (peace and blessings be upon him). The Prophet (peace and blessings be upon him) came. When he saw the rock, he took the pickaxe in his hand and put aside his garment. He said: "In the name of Allah." Then he struck it once, and a third of the rock broke. Then he said: "Allah is the Greatest! The keys of Syria have been granted. By Allah! I can see its red palaces at this moment." Then he struck it a second time, and another third of the rock broke. Then he said: "Allah is the Greatest! The keys of Persia have been granted. By Allah! I can see the white palace of Madain." Then he struck it a third time and said: "In the name of Allah!" The remaining part of the rock also broke, and he said: "Allah is the Greatest! The keys of Yemen have been granted. By Allah! I can see the gates of Sana'a."