In fact, the one who has only one concern (i.e. Allah’s content), will be sufficed (by Allah) with regard to all other concerns. There is a delicate point here, a statement related to Tawheed has the solution for all our problems: "Whatever takes place in the five continents since the creation of Adam till the Day of Resurrection is due to Allah's Will."

(Everything happens is due to Allah’s Will)

 This does not mean that Allah orders it or approves it, but rather He allows it. Think of a physician who got a beautiful son after ten years of marriage, but he finds out that his son has appendicitis and that his appendix should be surgically removed. This man allows to cut his son’s belly and make the surgery.

Everything that takes place in the five continents since the creation of Adam, peace be upon him, till the Day of Resurrection is decreed by Allah, and everything decreed by Allah shall take place, given Allah's Will is related to the absolute Wisdom. Hence, had things not taken place as they did, it would be lack of wisdom (Exalted be Allah above this assumption). 
(Allah’s Will relates to the absolute Wisdom and to the absolute Goodness)

The absolute Wisdom is related to the absolute Goodness, whose existence refutes the existence of the absolute evil. Therefore, the absolute evil does not exist in the universe, because it contradicts the Existence of Allah.