Venerable Dr. Walpola Rahula
"In the Dhammapada, there are three verses which are extremely important and essential in the Buddha’s Teaching. They are verses 277, 278, and 279 in Chapter 20:
277. All compound things are impermanent; those who realize this through insight- wisdom are freed from suffering. This is the path that leads to purity.
278. All compound things have suffering as their nature; those who realize this through insight-wisdom are freed from suffering. This is the path that leads to purity.
279. All states are without self; those who realize this through insight-wisdom are freed from suffering. This is the path that leads to purity.
The first two verses say: “All compound things (saṁkhārā) are impermanent” (sabbe saṁkhārā aniccā) and “All compound things have suffering as their nature” (sabbe saṁkhārā dukkhā). But the third verse says: “All states (dhammā) are without self” (sabbe dhammā anattā).
Here, it should be carefully observed that, in the first two verses, the word saṁkhārā “conditioned things, compound things” is used. But in its place in the third verse, the word dhammā “states” is used. Why does the third verse not use the word saṁkhārā “conditioned things, compound things” as in the previous two verses, and why does it use the term dhammā instead? Here lies the crux of the whole matter.
In the first two verses, the term saṁkhāra denotes the Five Aggregates, that is, all conditioned, interdependent, relative things and states, both physical and mental. If the third verse had said: “All saṁkhārā (“conditioned things, compound things”) are without self”, then, one might think that, although conditioned things are without Self, yet there may be a Self outside conditioned things, outside the Five Aggregates. It is in order to avoid misunderstanding that the term dhammā is used in the third verse.
The term “dhamma” is much wider than saṁkhāra. There is no term in Buddhist terminology wider than dhamma. It includes not only the conditioned things and states, but also the unconditioned, the Absolute, nibbāna. There is nothing in the universe or outside of it, good or bad, conditioned or unconditioned, relative or absolute, which is not included in this term. Therefore, it is quite clear that, according to this statement: “All states (dhammā) are without self”, there is no Self, no ātman, not only in the Five Aggregates, but nowhere else either outside them or apart from them.
This means, according to the Theravādin teaching, that there is no Self either in the individual (puggala) or in dhammas. The Mahāyāna Buddhist philosophy maintains exactly the same position, without the slightest difference, on this point, putting emphasis on dharma-nairātmya as well as on pudgala-nairātmya."
Note: As with many Westerners, my first exposure to the Buddha's teaching came through reading the Venerable Dr. Walpola Rahula's wonderful little book 'What the Buddha Taught.' The above is a section from the chapter entitled The Doctrine of No-Soul, and had a profound effect on me. (In fact, it still does today!) The entire book can be downloaded free of charge in PDF format from the kind people of the Charleston Buddhist Fellowship at the link below:
What the Buddha Taught