Do not seek again and again what you have already obtained. What is obtained here becomes the cycle of existences.

Punappunaṁ — again and again, repeatedly. The mind that is not content with what is achieved is the root of suffering. Each achievement generates new desire.

The Taṇhāvaṅgavagga is the chapter on thirst. Taṇhā — thirst, desire — is the second noble truth. This verse warns: what is obtained does not satisfy, because thirst is not in the object, it is in the mind.