As well as verbal prayer, Allah expects His servants to demonstrate how important they consider a prayer that asks for something to be, by their endeavor. This endeavor is called "prayer in action."
Prayer in action expresses one's exhausting all means to attain a desired end. In order to take the university exams, for instance, one needs to fill in the related forms, take courses and study. All these actions are prayers in action. Meanwhile, asking for success from Allah while accomplishing all these is also a prayer. The prayer in action is a basic act of worship that must be performed together with verbal prayer. Another example that clarifies verbal prayer and prayer in action is repentance. Asking for repentance and forgiveness for a sin is a verbal prayer. However, one's responsibility does not end here: one who prays to Allah to protect him from evil must also make some effort in this regard, and employ his will-power in situations where he has to choose between right and wrong. That is, he must truly repent and never return to his former ways after he has quit them. This would be his prayer in action.
Just as it is wrong for a person who only prays without involving himself in any kind of prayer in action, it is also wrong to say "I have accomplished this task," failing to pray verbally after completing the prayer in action.