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One good turn deserves another

A kindness is properly met with another kindness.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Idioms and Phrases with one good turn deserves another

one good turn deserves another

A favor should be returned in kind, as in I'll give you a ride next time—one good turn deserves another. This maxim was first recorded about 1400, and the converse, One bad turn deserves another, about 1500.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.