My first and initial reading of Lloyd-Jones’s classic Spiritual Depression: Its Causes and Cure elaborate on this trend. Lloyd-Jones asserts that a “depressed Christian is a contradiction in terms, and he is a very poor recommendation for the gospel (11).” In other words, he elaborates, “the man who is dejected and disquieted and miserable, who is unhappy and depressed always shows it in his face” (13).
It is true that this can be over-stated, but I think the principle of it is rather accurate. God created us to reflect glory with our faces. If our appearance does not reflect his glory as it ought, it is likely that it will be revealed in our countenance.