Full Idea
The duty to tell the truth applies only to those who deserve the truth.
Gist of Idea
Speak truth only to those who deserve the truth
Source
Michael J. Sandel (Justice: What's the right thing to do? [2009], 05)
Book Reference
Sandel,Michael J.: 'Justice: what's the right thing to do?' [Penguin 2010], p.132
A Reaction
[from Benjamin Constant, in opposition to Kant] I prefer the idea that we should use people 'after our own honour and dignity' (Hamlet), which means speaking the truth even to Donald Trump (for those of you who remember 2018). But not always.