चतुर्विधा भजन्ते मां जनाः सुकृतिनोऽर्जुनचतुर्विधा = 4 types of, भजन्ते = pray, मां = me, जनाः = people, सुकृतनः = of virtuous deeds, आर्तः = hurt, the afflicted, जिज्ञासु = the seeker of knowledge, अर्थार्थी = seeker of wealth or materialistic things, ज्ञानी = the one who is learned, भरतर्षभ = of Bharat Dynasty
आर्तो जिज्ञासुरर्थार्थी ज्ञानी च भरतर्षभ [७.१६]
Here in the 16th Shloka of Chapter 7 of Bhagvad Gita, is defined the nature of a Bhakta (devotee/seeker).
Four classes/kinds of people take to prayers. Prayers here are thoughts positive in nature which look outward of oneself for relief. It is not necessarily a hymn or chanting. It could be addressed to anyone you hold in high regard & faith (teacher, parents, seniors, king, nature, deities etc.) in the form of a heartfelt request for help.
First one is आर्तः - someone who is in any kind of pain. The afflicted one, who is overwhelmed with anxiety, worry and sadness. As anxiety, worries, hurt, afflictions are nothing but a state of mind and born out of our very own thoughts which are negative in nature; a good way to counter them would be to put forth our very own thoughts which are positive in nature. It is not easy to think of positive thoughts when one is in the numbness of pain, hence a prayer (admission of surrender and asking for support) is the starting point. It is an easy antidote to all the mental negativity and helps us bear with it till our sense of reasoning and analysis is back.
Second is जिज्ञासु - the seeker of knowledge. The one who wants to learn.
Third is अर्थार्थी - the one who seeks material success.
Fourth is ज्ञानी - the learned one. The one who has understood the truth. Just because his prayers (of any kind) have been answered doesn't stop him for being a seeker. It is just like being a traveller who remains a traveller even when he has reached his destination.