悦しきかな汝蘭室の友に交りて麻畝の性と成る - How gratifying! You have associated with a friend in the orchid room and have become as straight as mugwort growing among hemp.

本文
鳩 化して鷹と為り 雀 変じて蛤と為る、悦しきかな 汝 蘭室の友に交りて麻畝の性と成る

立正安国論
（３１頁）
文応元年７月
（１２６０年）

通解（意訳）
古事に「鳩化して鷹となり、雀（福良雀という、雀（すずめ）の形のような貝）が変じて蛤（はまぐり）となる」とあるように、人は善き友（善知識）と交わることで、より善い人間になることができる。

悦ばしいことに、あなたは蘭室の友（蘭の香りのように人徳の薫り高い人）に交わって感化されて、蓬（よもぎ）のように曲がりがちな性格が、真っ直ぐに育つ麻畑の中に蓬が交わって正されたように、素直で真っ直ぐな性格になれた。

English Gosho
 The dove has changed into a hawk, the sparrow into a clam.
 How gratifying! You have associated with a friend in the orchid room and have become as straight as mugwort growing among hemp.

" On Establishing the Correct Teaching
 for the Peace of the Land "
July, 1260.
"The Writings of Nichiren Daishonin", Vol.1, p. 23

[ --- ] is liberal translation.

Interpretation (liberal translation)
 When "I become a dove and become the hawk, and a sparrow (shellfish such as the form of the sparrow) changes and becomes the clam ," folk history has it.
In this way, the person is to associate with a good friend, and, as for the person, it can be to a better human being.
 How gratifying! You were influenced like the fragrance of the orchid by the friend of a splendid natural virtue.
 I was used to the character that the bent character was obedient, and was honest like your mugwort. As the mugwort which crossed in the linen field which grew straight up grew straight in the same way.

参考文献：「日蓮大聖人御書全集」
「御書をひもとく」「英語で学ぶ御書」　第三文明社
Bibliography : "The Writings of Nichiren Daishonin"
"The Record of The Orally Transmitted Teachings"