“When a person was so consistently wrong, it was time to give up having opinions.”

Source: "English and the Discipline of Ideas" (1920), p. 65

William Martin, The Best Liberal Quotes Ever: Why the Left is Right, Sourcebooks, Inc., 2004, ISBN 1402203098, p. 204
Attributed

Navarette v. California, 134 S. Ct. 1683, 1697, 188 L. Ed. 2d 680 (2014).
2010s

Variant translation:
It is very important to give advice to a man to help him mend his ways. It is a compassionate and important duty. However, it is extremely difficult to comprehend how this advice should be given. It is easy to recognise the good and bad points in others. Generally it is considered a kindness in helping people with things they hate or find difficult to say. However, one impracticality is that if people do not take in this advice they will think that there is nothing they should change. The same applies when we try to create shame in others by speaking badly of them. It seems outwardly that we are just complaining about them. One must get to know the person in question. Keep after him and get him to put his trust in you. Find out what interests he has. When you write to him or before you part company, you should express concrete examples of your own faults and get him to recall to mind whether or not he has the same problems. Also positively praise his qualities. It is important that he takes in your comments like a man thirsting for water. It is difficult to give such advice. We cannot easily correct our defects and weak points as they are dyed deeply within us. I have had bitter experience of this.
Hagakure (c. 1716)
Source: Hagakure: The Book of the Samurai
Context: To give a person an opinion one must first judge well whether that person is of the disposition to receive it or not. One must become close with him and make sure that he continually trusts one's word. Approaching subjects that are dear to him, seek the best way to speak and to be well understood.
Context: To give a person one's opinion and correct his faults is an important thing. It is compassionate and comes first in matters of service. But the way of doing this is extremely difficult. To discover the good and bad points of a person is an easy thing, and to give an opinion concerning them is easy, too. For the most part, people think that they are being kind by saying the things that others find distasteful or difficult to say. But if it is not received well, they think that there is nothing more to be done. This is completely worthless. It is the same as bringing shame to a person by slandering him. It is nothing more than getting it off one's chest.
To give a person an opinion one must first judge well whether that person is of the disposition to receive it or not. One must become close with him and make sure that he continually trusts one's word. Approaching subjects that are dear to him, seek the best way to speak and to be well understood. Judge the occasion, and determine whether it is better by letter or at the time of leave-taking. Praise his good points and use every device to encourage him, perhaps by talking about one's own faults without touching on his, but so that they will occur to him. Have him receive this in the way that a man would drink water when his throat is dry, and it will be an opinion that will correct faults.
This is extremely difficult. If a person's fault is a habit of some years prior, by and large it won't be remedied. I have had this experience myself. To be intimate with all one's comrades, correcting each other's faults, and being of one mind to be of use to the master is the great compassion of a retainer. By bringing shame to a person, how could one expect to make him a better man?

Source: The Tales of Alvin Maker, Alvin Journeyman (1995), Chapter 14.

The Secret of the Golden Flower (1931) Commentary by C.G.Jung in CW 13: Alchemical Studies. P. 60

Source: He's Just Not That Into You: The No-Excuses Truth to Understanding Guys

Horton Hears a Who! (1954)
Source: Fox in Socks