In plain words
Then there must be a stamp on the cover. If you stick on a stamp, write the address and post it, it will go, be it a thousand miles, two thousand miles or five thousand miles. If you do not stick on a stamp, it will not reach even the house next door. What is this stamp? Purity of heart. Now, here is pure white paper, clean, as big as this hall. If it is given to you, you fold it, put it on the table and set a paperweight on it. But if a hundred-rupee note of 3/5 size is given, and it is very dirty, what do you do when it is given to you? You put it in a Godrej cupboard and lock it. Even when white paper a thousand times larger than that is given, you do not care for it. You are throwing it away. This dirty paper has become oily with who knows what, and who knows what sums have been written on it too; such dirty paper you take away, put in the Godrej and lock. What is the reason for its value? Just this: it carries the Reserve Bank stamp. Only because that stamp is on it has such dirty paper got so much value. This one has no such stamp, so though it is so holy, so pure and so wide, you push it aside as having no value.
That is why the Āzhvār said: "O Lord, I worship You with purity of heart." That purity of heart is the stamp of value. Without that purity, however much you do, there is no use. But at each time, each substance, according to the effect of each circumstance, turns into some good or some bad. If you hand a cup of cold water to a man who is very healthy and is thirsty, he gets great comfort and joy. It does him great good and gives him joy. If that same cold water is given to a patient with a high temperature, the doctor stops it, saying, "Do not give it." From this, pneumonia may come. This cup of cold water does good to one and harm to another. In the same way, according to the effect of each one's circumstances, purity of heart and impurity of heart, these go on giving their several fruits. Man tries to take pride, saying, "I am a man." What makes you proud? On what do you rest your pride? Are you proud when you look at your wealth? That wealth is gone in a moment. It moves away. Well then, are you proud when you look at your beauty? After you reach a certain age, all this beauty melts away as snow melts. Well then, are you proud when you look at your strength? As a flower that bloomed at daybreak withers in the evening, this withers. Well then, are you proud when you look at your power of intellect and your cleverness? The fox is cleverer than you. So you are far less than it. But you are not more than it, are you! How then can you be proud?