Here are two examples of the Avestan wisdom translated by Sorabjee Pestonjee Kanga in his collection entitled: The Metrical Version of the Gathas in English, Bombay, 1934.

"The man whose heart is pure uplifts the world
By strength of his good thought, good word, good deed,
He holds up high the flag of faith unfurled,
He spares no pains in preaching Mazda’s creed,
Of peaceful brotherhood he sows the seed.
Spiritual truth, the source of every bliss,
Leads him onward, and he must needs succeed,
Let all right-thinking men remember this
No chance of doing good they ever miss."
Avesta, Gatha Vohukhshathra v. 20

"Now offer up to Him your solemn songs
To the Omnipotent Lord, Who loveth all,
To Whom alone the universe belongs.
Good thought, good word, good deed, these words recall,
Their potent charm will thrive you here below;
Hereafter give you joys that never pall.
To gain His grace divine do not be slow,
Adhere to truth, the rest He will bestow."
Avesta, Gatha Ushtavaiti v.8.