Ukkacelasutta

Suttapiṭaka · Saṁyuttanikāya · Mahāvaggasaṁyutta · Vol. 19 · Section 746

[746] Bhikkhus, whoever, either now or after my passing, shall dwell as islands unto themselves (attadīpā), with themselves as refuge, with no other refuge; with the Dhamma as their island, with the Dhamma as their refuge, with no other refuge — those bhikkhus of mine, bhikkhus, shall be the topmost (tamatagge), that is, whoever are desirous of training. End of the Fourth Sutta Bāhiyasutta Virtue as the Beginning of Wholesome States

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 19 · Section 713 — Gilānasutta