Why should we pray?

In all religion the most important things in pray is clearing your mind from any thoughts, why god asks us for that???
when you isolate your negative thoughts that give you the chance to look deep in your self and discover it.

How will you know your self without looking in it, we always concentrate on other people and external situation what will happened if we focused on our inside instead of other, changing our self is easier than changing external situations and people around us.

In addition when you clear your mind and arrive silent state, you make permission for cosmic energy to pass through you and charge you. when you have more energy you have a power to achieve more tasks in your day.