Consider a grid of size 4 by 4 (i.e. sixteen squares), where all squares should get a colour. The coloured grid should meet the following conditions:

4 squares should be coloured blue,
3 squares should be coloured red,
3 squares should be coloured white,
3 squares should be coloured green,
3 squares should be coloured yellow, and
no colour may appear more than once in any horizontal, vertical, or diagonal line.

How can the grid be coloured?

Two Egyptian camel drivers were fighting for the hand of the daughter of the sheikh of Arab. The sheikh, who liked neither of these men to become the future husband of his daughter, came up with a clever plan: a race would determine who of the two men would be allowed to marry his daughter. Therefore, the sheikh organised a camel race. Both camel drivers had to travel from Cairo to Abbudzjabbu, and the one whose camel would arrive last in Abbudzjabbu, would be allowed to marry the sheikh’s daughter.
The two camel drivers, realising that this could become a rather lengthy expedition, finally decided to consult the Wise Man of their village. Arrived there, they explained him the situation, upon which the Wise Man raised his cane and spoke four wise words. Relieved, the two camel drivers left his tent: they were ready for the contest!

Which four wise words did the Wise Man speak?