Authors:

If a good face is a letter of recommendation, a good heart is a letter of credit.

"Hoyt's New Cyclopedia Of Practical Quotations" by Jehiel Keeler Hoyt, p. 250-52, What Will He Do With It? (1858), Book II. Title of Ch, XI., 1922.
If a good face is a letter of recommendation, a good heart is a letter of credit.