You ask me why I have no verses sent?
For fear you should return the compliment.

[Cur non mitto meos tibi, Pontiliane, libellos?
Ne mihi tu mittas, Pontiliane, tuos.]

Martial (AD c.39-c.103) Spanish Roman poet, satirist, epigrammatist [Marcus Valerius Martialis]

Epigrams [Epigrammata], Book 7, epigram 3 (7.3) (AD 92) [tr. Hay (1755)]
    (Source)

Compare to Epigram 5.73. (Source (Latin)). Alternate translations:

Why send I not to thee these books of mine?
'Cause I, Pontilian, would be free from thine.
[tr. Wright (1663)]

Why I send thee, Pontilian, not one of my writings?
It is lest thou, too gen'rous, return thine enditings.
[tr. Elphinston (1782), 12.10]

Why do I not send you my books, Pontilianus? Lest you should send me yours, Pontilianus.
[tr. Bohn's Classical (1859)]

Why, sir, I don't my verses send you,
Pray, would you have the reason known?
The reason is -- for fear, my friend, you
Should send me, in return, your own.
[tr. Webb (1879)]

You ask me why I send you not my books?
Lest you should send me yours, my friend, in turn.
[ed. Harbottle (1897)]

I never send my books, it’s true.
Know why? You’d send me your books too.
[tr. West (1912), "Reply"]

Why do I not send you my works, Pontilianus? That you, Pontilianus, may not send yours to me.
[tr. Ker (1919)]

You ask me why my books were never sent?
For fear you might return the compliment.
[tr. Pott & Wright (1921)]

Pontilianus asks why I omit
To send him all the poetry that is mine;
The reason is that in return for it,
Pontilianus, thou might'st send me thine.
[tr. Duff (1929)]

You ask me why I do not send you
All my latest publications?
Let in turn you send me, sir,
All your latest lucubrations!
[tr. Marcellino (1968)]

Why have I never sent
My works to you, old hack?
For fear the compliment
Comes punishingly back.
[tr. Michie (1972)]

Why don't I send you my little books, Pontilianus? Fore fear you might send me yours, Pontilianus.
[tr. Shackleton Bailey (1993)]

Why don’t I send you my little books?
Pontilianus, lest you send me yours.
[tr. Kline (2006), "No thanks"]

You ask me why I send you not my book?
For fear you'll say, "Here's my work -- take a look."
[tr. Wills (2007)]

Why don’t I send my books to you?
For fear you’d send me your books, too.
[tr. McLean (2014)]

You wonder why my little book is overdue,
dear Pontilianus?
It’s just that I don’t want to look at one from you.
[tr. Juster (2016)]

You ask me why I’ve sent you no new verses?
There might be reverses.
[tr. Burch (c. 2017)]

You fret I haven’t sent you, Wade,
My latest book for free;
The fact is that I’m too afraid
You’d send your book to me.
[tr. Mitchell]