user135: I came across 'The Chant of Metta' (Metta Gatha), in a beautiful rendition by Imee Ooi in this YouTube video.
Here is the full text in Pali, with English translation: THE CHANT OF METTA
Is this chant from the Tipitaka or is it a later composition? The Karaniya Metta Sutta from Tipitaka has different wordings in this translation.

user5838: The popular chant of metta is originated from the Theravada Tripitaka. This can be found in Kuddaka Nikaya->Patisambhidamagga->Yuganaddawagga Mettakatha
Read from page 130

user254: The chant which you're asking about included in, for example, The Complete Book
of
Pâli
Chanting
(Theravada Tradition)
By
Dr. Phra Achan Dhammarato, Bhikkhû, PhD. (page 152).
I think that it is traditional (not written recently by or for Imee Ooi).
It starts with "homi", i.e. "May I be".
That's compatible with the commentary in The Path of Purification, which says on page 292,

First of all it should be developed only towards oneself, doing it repeatedly thus: "May I be happy and free from suffering" or "May I keep myself free from enmity, affliction, and anxiety and live happily."

The next paragraphs explain why that "does not conflict with what is said in the texts": maybe that's evidence that this formula, i.e. starting with the first person singular, isn't found in the (earlier) suttas.

135: <p>I came across 'The Chant of Metta' (<em>Metta Gatha</em>), in a beautiful rendition by Imee Ooi in this <a href="https://www.youtube.com/watch?v=S5JAVk3Qwi8" rel="nofollow">YouTube video</a>.</p>

<p>Here is the full text in Pali, with English translation: <a href="http://satipatthana.ca/articles/06the_chant_metta.pdf" rel="nofollow">THE CHANT OF METTA</a></p>

<p>Is this chant from the Tipitaka or is it a later composition? The Karaniya Metta Sutta from Tipitaka has different wordings in <a href="http://www.accesstoinsight.org/tipitaka/kn/snp/snp.1.08.amar.html" rel="nofollow">this</a> translation.</p>
 5838: <p>The popular chant of metta is originated from the Theravada Tripitaka. This can be found in <strong>Kuddaka Nikaya->Patisambhidamagga->Yuganaddawagga Mettakatha</strong></p>

<p><a href="http://static.sirimangalo.org/pdf/patisambhidamagga2.pdf" rel="nofollow">Read from page 130</a></p>
 254: <p>The chant which you're asking about included in, for example, <a href="http://fellowdesigns.com/main/images/stories/palichanting_urw_csx_short.pdf" rel="nofollow">The Complete Book
of
Pâli
Chanting
(Theravada Tradition)
By
Dr. Phra Achan Dhammarato, Bhikkhû, PhD.</a> (page 152).</p>

<p>I think that it is traditional (not written recently by or for Imee Ooi).</p>

<p>It starts with "<em>homi</em>", i.e. "May I be".</p>

<p>That's compatible with the commentary in <a href="http://what-buddha-said.net/library/pdfs/PathofPurification2011.pdf" rel="nofollow">The Path of Purification</a>, which says on page 292,</p>

<blockquote>
  <p>First of all it should be developed only towards oneself, doing it repeatedly thus: "May I be happy and free from suffering" or "May I keep myself free from enmity, affliction, and anxiety and live happily."</p>
</blockquote>

<p>The next paragraphs explain why that "does not conflict with what is said in the texts": maybe that's evidence that this formula, i.e. starting with the first person singular, isn't found in the (earlier) suttas.</p>
