Yo imasmiṃ dhammavinaye
Appamatto vihassati!
Pahāya jātisaṃsāraṃ dukkhassantaṃ karissatī.
Listen: http://host.pariyatti.org/dwob/digha_nikaya_2_185.mp3

With firm resolve, guard your own mind!
Who so untiringly pursues the Dhamma and the Discipline
Shall go beyond the round of births and make an end of suffering.

Dīgha Nikāya 2.185
http://tipitaka.org/romn/cscd/s0102m.mul2.xml#para185
Last Days of the Buddha: The Maha-parinibbana Sutta (revised edition), translated from Pāli by Sister Vajira & Francis Story