Variant: We will have to repent in this generation not merely for the hateful words and actions of the bad people but for the appalling silence of the good people.
“Men repent speaking ten times, for once that they repent keeping silence.”
            The Dignity of Human Nature (1754) 
Context: Men repent speaking ten times, for once that they repent keeping silence.
It is an advantage to have concealed one's opinion; for by that means you may change your judgment of things (which every wise man fmds reason to do) and not be accused of fickleness.
        
Help us to complete the source, original and additional information
James Burgh 49
British politician 1714–1775Related quotes
“678. More have repented speech then silence.”
Jacula Prudentum (1651)
                                        
                                        Letter to Reverdy Johnson (26 July 1862) 
1860s
                                    
                                        
                                        "Remaining Awake Through a Great Revolution", sermon at the National Cathedral, 31 March 1968, published in A Testament of Hope (1986) 
1960s 
Source: A Testament of Hope: The Essential Writings and Speeches
                                    
                                        
                                        Forse, se tu gustassi anco una volta
La millesima parte de la gioie
Che gusta un cor amato riamando,
Diresti, ripentita, sospirando:
Perduto è tutto il tempo
Che in amar non si spende. 
Act I, scene i, lines 26–31. 
Variant translations: 
All time is truly lost and gone
Which is not spent in serving love. 
All time is lost that is not spent in love. 
Lost is all the time that you don't spend in love. 
Aminta (1573)
                                    
“He or silence keeps or speaks in season.”
Source: Seven Against Thebes (467 BC), line 619 (tr. Anna Swanwick)
The Rubaiyat (1120)