Hoyt & Roberts, comps. Hoyt’s New Cyclopedia of Practical Quotations. 1922.

Proof

You may prove anything by figures.
Quoted by Carlyle—Chartism. No. 2.

You cannot demonstrate an emotion or prove an aspiration.
John Morley—Rousseau. P. 402.

For when one’s proofs are aptly chosen,
Four are as valid as four dozen.
Prior—Alma. Canto I. End.

Prove all things; hold fast that which is good.
I Thessalonians. V. 21.