Salabham natimanneyya n' annesam pihayam care
Annesam pihayam bhikkhu samadhim n'adhigacchati.
One should not despise what one receives, and one should not envy (the gain of) others. The bhikkhu who envies others does not attain. 
DESPISE NOT WHAT ONE GETS
Appa labho' pi ce bhikkhu salabham n' atimannati
Tam ve deva pasamsanti suddhajivim atanditam.
Though receiving but little, if a bhikkhu does not despise his own gains,
even the gods praise such a one who is pure in livelihood and is not slothful. 
Once, a bhikkhu of the Buddha was very friendly with a bhikkhu belonging to the faction led by Devadatta, the opponent of the Buddha. He visited Devadatta's monastery and stayed there for a few days, eating, sleeping and enjoying the comforts of that monastery. Other bhikkhus reported him to the Buddha who sent for the bhikkhu and asked him whether this was true. The bhikkhu admitted that he had stayed at the monastery of Devadatta for a few days, but he told the Buddha that he had not embraced the teaching of Devadatta.
The Buddha then admonished him, 'My son, even though you have not embraced the heretical doctrine of Devadatta, you are going about as if you were one of his followers, and enjoying the comforts provided elsewhere. A bhikkhu should be contented with what he gets and should not covet other people's gains. A bhikkhu who is filled with envy at the good fortune of others will not attain concentration (samadhi), or Insight,*or the Path that leads to Nibbana. Only the bhikkhu who is contented with whatever he gets will be able to attain Concentration, Insight and. the Correct Path.'
- Samadhi,both mundane and supramundane concentration.
*Insight (Vipassana) is the intuitive light flashing forth and exposing the truth of impermanency (anicca), unsatisfactoriness (dukkha), and no soul (anatta). Discipline regulates words and deeds; concentration controls the mind, but it is Insight that perceives things as they are and not what they appear to be. Insight is not the result of mere intellectual understanding, but is won through direct meditative observation of one's own bodily and mental processes.