The noble-minded worry about their lack of ability, not about people’s failure to recognize their ability.

[君子病無能焉、不病人之不己知也]

Confucius (c. 551- c. 479 BC) Chinese philosopher, sage, politician [孔夫子 (Kǒng Fūzǐ, K'ung Fu-tzu, K'ung Fu Tse), 孔子 (Kǒngzǐ, Chungni), 孔丘 (Kǒng Qiū, K'ung Ch'iu)]

The Analects [論語, 论语, Lúnyǔ], Book 15, verse 19 (15.19) (6th C. BC – AD 3rd C.) [tr. Hinton (1998)]
    (Source)

(Source (Chinese)). See also 1.16, 4.14, 14.30. Legge and other early translators numbered this, as shown below, 15.18. Alternate translations:

The superior man is distressed by his want of ability. He is not distressed by men's not knowing him.
[tr. Legge (1861), 15.18]

The trouble of the superior man will be his own want of ability: it will be no trouble to him that others do not know him.
[tr. Jennings (1895), 15.18]

A wise and good man should be distressed that he has no ability ; he should never be distressed that men do not take notice of him.
[tr. Ku Hung-Ming (1898), 15.18]

The noble man is pained over his own incompetency, he is not pained that others ignore him.
[tr. Soothill (1910), 15.18]

The proper man is irritated by his incapacities, not irritated by other people not recognizing him.
[tr. Pound (1933), 15.18]

A gentleman is distressed by his own lack of capacity; he is never distressed at the failure of others to recognize his merits.
[tr. Waley (1938), 15.18]

The perfect gentleman complains about his own inabilities; not about people’s ignorance of himself.
[tr. Ware (1950)]

The gentleman is troubled by his own lack of ability, not by the failure of others to appreciate him.
[tr. Lau (1979)]

The gentleman is pained at the lack of ability within himself; he is not pained at the fact that others do not appreciate him.
[tr. Dawson (1993)]

A gentleman resents his incompetence; he does not resent his obscurity.
[tr. Leys (1997)]

The gentleman worries about his incapability; he does not worry about men not knowing him.
[tr. Huang (1997)]

A gentleman worries about that he does not have the ability, does not worry about that others do not understand him.
[tr. Cai/Yu (1998), #403]

Exemplary persons (junzi) are distressed by their own lack of ability, not by the failure of others to acknowledge them.
[tr. Ames/Rosemont (1998)]

The gentleman takes it as a fault if he is incapable of something; he does not take it as a fault if others do not know him.
[tr. Brooks/Brooks (1998)]

The gentleman is distressed by his own inability, rather than the failure of others to recognize him.
[tr. Slingerland (2003)]

The gentleman is troubled by his own lack of ability. He is not troubled by the fact that others do not understand him.
[tr. Watson (2007)]

The gentleman is worried about his own lack of ability and not about the fact that others do not appreciate him.
[tr. Chin (2014)]

A Jun Zi is disappointed about his own incompetency. He is not distressed that he is not known by others.
[tr. Li (2020)]