貧賤之交不可忘
pín​jiàn​zhī​jiāo​bù​kě​wàng

one should not forget friends from poor times

Senses

贫贱之交不可忘/ 貧賤之交不可忘 pín​jiàn​zhī​jiāo​bù​kě​wàng one should not forget friends from poor times

A friend made during times of poverty and hardship should never be forgotten; usually paired with 糟糠之妻不下堂 zāo​kāng​zhī​qī​bù​xià​táng to emphasize not abandoning those who shared one's struggles

References

see 贫贱之交不可忘/貧賤之交不可忘 → 糟糠之妻不下堂/糟糠之妻不下堂
see 糟糠之妻不下堂/糟糠之妻不下堂 → 贫贱之交不可忘/貧賤之交不可忘