Virtue is not left to stand alone. He who practises it will have neighbors.

[德不孤、必有鄰。]

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 4, verse 25 (4.25) (6th C. BC – AD 3rd C.) [tr. Legge (1861)]
    (Source)

Differing commentary on the text can be found; it may mean that virtue attracts others to its side, or it may be a comment on virtue needing to be practiced in a social setting.

(Source (Chinese)). Alternate translations:

Virtue dwells not alone: she must have neighbors.
[tr. Jennings (1895)]

Moral worth is never left alone; society is sure to grow round him.
[tr. Ku Hung-Ming (1898)]

Virtue never dwells alone; it always has neighbors.
[tr. Soothill (1910)]

Virtue attracts friends.
[tr. Soothill (1910), Alternate]

Candidness is not fatherless, it is bound to have neighbors.
[tr. Pound (1933)]

Moral force (tê) never dwells in solitude; it will always bring neighbors.
[tr. Waley (1938)]

High moral conduct does not remain alone; it is sure to attract neighbors.
[tr. Ware (1950)]

Virtue never stands alone. It is bound to have neighbors.
[tr. Lau (1979)]

Virtue is not solitary. It is bound to have neighbors.
[tr. Dawson (1993)]

Virtue is not solitary; it always has neighbors.
[tr. Leys (1997)]

The virtuous are not solitary. They surely have neighbors.
[tr. Huang (1997)]

A virtuous person is not alone, certainly has his companions.
[tr. Cai/Yu (1998)]

Excellent persons (de) do not dwell alone; they are sure to have neighbors.
[tr. Ames/Rosemont (1998)]

Virtue is not solitary; it must have neighbors.
[tr. Brooks/Brooks (1998)]

Integrity's never alone. It always has neighbors.
[tr. Hinton (1998)]

Virtue is never solitary; it always has neighbors.
[tr. Slingerland (2003)]

Virtue is not alone. It invariably has neighbors.
[tr. Watson (2007)]

Virtue does not stand alone. It is bound to have neighbors.
[tr. Annping Chin (2014)]

A virtuous person is never lonely because there is always a comrade nearby.
[tr. Li (2020)]