If you desire to be pure, have firm faith, and slowly go on with your devotional practices without wasting your energy in useless scriptural discussions and arguments. Your little brain will otherwise be muddled.
The way of love is as true as the way of knowledge. All paths ultimately lead to the same Truth. But as long as God keeps the feeling of ego in us, it is easier to follow the path of love.
You must know that there are different tastes. There are also different powers of digestion... different temperaments... differences in the capacity to comprehend.
One cannot attain divine knowledge till one gets rid of pride. Water does not stay on the top of a mound; but into low land it flows in torrents from all sides.
The physicians of one class feel the patients and go away, merely prescribing medicine. As they leave the room they simply ask the patient to take the medicine. They are the poorest class of physicians.
When an unbaked pot is broken, the potter can use the mud to make a new one; but when a baked one is broken, he cannot do the same any longer. So when a person dies in a state of ignorance, he is born again; but when he becomes well baked in the fire of true knowledge and dies a perfect man, he is not born again.
You speak of doing good to the world. Is the world such a small thing? And who are you, pray, to do good to the world? First realise God, see Him by means of spiritual discipline. If He imparts power you can do good to others; otherwise not.
Little children play with dolls in the outer room just as they like, without any care of fear or restraint; but as soon as their mother comes in, they throw aside their dolls and run to her crying, "Mamma, mamma." You too, are now playing in this material world, infatuated with the dolls of wealth, honour, fame, etc., If however, you once see your Divine Mother, you will not afterwards find pleasure in all these. Throwing them all aside, you will run to her.