Reference request for "the Buddha takes the Dhamma as his superior" In what Pali sutta[s] does the Buddha says something approximately like,


  Everyone needs someone better than them, who they can revere and who can guide them: who will be their teacher. But there is no-one better than the Buddha: and so I take the Dhamma as my guide/superior/teacher.
From the Garava Sutta (SN 6.2):


  I have heard that on one occasion, when the Blessed One was newly
  Self-awakened, he was staying at Uruvela on the bank of the Nerañjara
  River, at the foot of the Goatherd's Banyan Tree. Then, while he was
  alone and in seclusion, this line of thinking arose in his awareness:
  "One suffers if dwelling without reverence or deference. Now on what
  brahman or contemplative can I dwell in dependence, honoring and
  respecting him?"
  
  Then the thought occurred to him: "It would be for the sake of
  perfecting an unperfected aggregate of virtue that I would dwell in
  dependence on another brahman or contemplative, honoring and
  respecting him. However, in this world with its devas, Maras, &amp;
  Brahmas, in this generation with its brahmans and contemplatives, its
  royalty and common-folk, I do not see another brahman or contemplative
  more consummate in virtue than I, on whom I could dwell in dependence,
  honoring and respecting him.
  
  "It would be for the sake of perfecting an unperfected aggregate of
  concentration that I would dwell in dependence on another brahman or
  contemplative, honoring and respecting him. However, in this world
  with its devas, Maras, &amp; Brahmas, in this generation with its brahmans
  and contemplatives, its royalty and common-folk, I do not see another
  brahman or contemplative more consummate in concentration than I, on
  whom I could dwell in dependence, honoring and respecting him.
  
  "It would be for the sake of perfecting an unperfected aggregate of
  discernment that I would dwell in dependence on another brahman or
  contemplative, honoring and respecting him. However, in this world
  with its devas, Maras, &amp; Brahmas, in this generation with its brahmans
  and contemplatives, its royalty and common-folk, I do not see another
  brahman or contemplative more consummate in discernment than I, on
  whom I could dwell in dependence, honoring and respecting him.
  
  "It would be for the sake of perfecting an unperfected aggregate of
  release that I would dwell in dependence on another brahman or
  contemplative, honoring and respecting him. However, in this world
  with its devas, Maras, &amp; Brahmas, in this generation with its brahmans
  and contemplatives, its royalty and common-folk, I do not see another
  brahman or contemplative more consummate in release than I, on whom I
  could dwell in dependence, honoring and respecting him.
  
  "It would be for the sake of perfecting an unperfected aggregate of
  knowledge and vision of release that I would dwell in dependence on
  another brahman or contemplative, honoring and respecting him.
  However, in this world with its devas, Maras, &amp; Brahmas, in this
  generation with its brahmans and contemplatives, its royalty and
  common-folk, I do not see another brahman or contemplative more
  consummate in knowledge and vision of release than I, on whom I could
  dwell in dependence, honoring and respecting him.
  
  "What if I were to dwell in dependence on this very Dhamma to which I
  have fully awakened, honoring and respecting it?"
  
  Then, having known with his own awareness the line of thinking in the
  Blessed One's awareness — just as a strong man might extend his flexed
  arm or flex his extended arm — Brahma Sahampati disappeared from the
  Brahma-world and reappeared in front of the Blessed One. Arranging his
  upper robe over one shoulder, he saluted the Blessed One with his
  hands before his heart and said to him: "So it is, Blessed One! So it
  is, One-Well-Gone! Those who were Arahants, Rightly Self-awakened Ones
  in the past — they, too, dwelled in dependence on the very Dhamma
  itself, honoring and respecting it. Those who will be Arahants,
  Rightly Self-awakened Ones in the future — they, too, will dwell in
  dependence on the very Dhamma itself, honoring and respecting it. And
  let the Blessed One, who is at present the Arahant, the Rightly
  Self-awakened One, dwell in dependence on the very Dhamma itself,
  honoring and respecting it."
  
  That is what Brahma Sahampati said. Having said that, he further said
  this:
  
  Past Buddhas,
  future Buddhas,
  &amp; he who is the Buddha now,
  removing the sorrow of many —
  
  all have dwelt,
  will dwell, he dwells,
  revering the true Dhamma.
  This, for Buddhas, is a natural law.
  
  Therefore one who desires his own good,
  aspiring for greatness,
  should respect the true Dhamma,
  recollecting the Buddhas' Teaching.