Through thick and thin (Dryden). Through evil and through good report; through stoggy mud and stones only thinly covered with dust.
Through perils both of wind and limb She followed him through thick and thin.
“Thick and thin blocks” are pulley-blocks with two sheaves of different thickness, to accommodate different sizes of ropes.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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