Krishna says that there are four types of devotees.
The first one wants to come out of difficulties and misery he is facing in life. The second one desires to have physical possessions and worldly pleasures. Most devotees fall in these two categories irrespective of culture, gender, belief systems etc.
Krishna says that these two kinds of devotees pray and perform rituals to various Devatas . It is akin to approaching an appropriate doctor based on the ailment one suffers from. Krishna further says that the desires of these devotees are fulfilled because of their Shradha . It is in essence, a form of surrender.
The following example will illustrate Shradha . Two farmers who have adjacent farms decide to dig a well to irrigate their farms. The first farmer would dig for a day or two and upon not finding any water would change the location and start digging afresh. The second farmer persistently kept digging at the same place. By the end of the month, the first farmer is left with many ditches and the second one got water from the well. Even when our senses don't find anything tangible (like water in this case), it is inner Shradha that keeps us moving as in the case of the second farmer. Shradha is a fearless positive force and free of doubt.
Krishna hints that he is behind this Shradha which results in success. Shradha in our relationships, family ties and profession has the power to achieve miracles.
The third kind of devotee is about to cross the boundary of desires. He is a curious person and seeks knowledge of self. The fourth kind is a Gyani (a wise one) and he has crossed the boundary of desires. He sees the Lord in everything and everywhere and has attained union with the almighty.
Source - Daily World