The Art of Poetry on a New Plan (1761), vol. ii. p. 147.
The saying "he who fights and runs away may live to fight another day" dates at least as far back as Menander (ca. 341–290 B.C.), Gnomai Monostichoi, aphorism #45: ἀνήρ ὁ ϕɛύγων καὶ ράλίν μαχήɛṯαί (a man who flees will fight again). The Attic Nights (book 17, ch. 21) of Aulus Gellius (ca. 125–180 A.D.) indicates it was already widespread in the second century: "...the orator Demosthenes sought safety in flight from the battlefield, and when he was bitterly taunted with his flight, he jestingly replied in the well-known verse: The man who runs away will fight again".

“By sports like these are all their cares beguil'd;
The sports of children satisfy the child.”

Oliver Goldsmith

Source: The Traveller (1764), Line 153.

“Silence gives consent.”

Oliver Goldsmith

Act II.
The Good-Natured Man (1768)

“O Memory! thou fond deceiver.”

Oliver Goldsmith

Act I.
The Captivity, An Oratorio (1764)

“Our greatest glory is not in never falling, but in rising every time we fall.”

Oliver Goldsmith

Variant: Our greatest glory consists not in never falling, but in rising every time we fall.
Source: The Citizen of the World, Or, Letters from a Chinese Philosopher, Residing in London, to His Friends in the Country, by Dr. Goldsmith

“Ask me no questions, and I'll tell you no fibs.”

Oliver Goldsmith She Stoops to Conquer

She Stoops to Conquer
She Stoops to Conquer (1771), Act III
Variant: Ask me no questions, and I'll tell you no lies.

“The first time I read an excellent book, it is to me just as if I had gained a new friend. When I read a book over I have perused before, it resembles the meeting with an old one.”

Oliver Goldsmith

Source: The Citizen of the World, Or, Letters from a Chinese Philosopher, Residing in London, to His Friends in the Country, by Dr. Goldsmith

“You can preach a better sermon with your life than with your lips.”

Oliver Goldsmith

“Luke's iron crown, and Damien's bed of steel.”

Oliver Goldsmith

Source: The Traveller (1764), Line 436.

“The best-humour'd man, with the worst-humour'd Muse.”