let bygones be bygones
Definition:  when one says they have forgiven someone for something, they should not keep bringing the issue up, the issue should be forgotten and be left in the past
Usage:  I remember you saying you have forgiven me for this, but you keep reminding me of it, may we please just let bygones be bygones

SEPEDI
Translation:  tlogela tšeo di fetilego e be tšeo di fetilego
Proverb: a di je di šie marapo

XITSONGA
Translation:  pfumelela leswi hundzeke swi va leswi hundzeke
Proverb: swimanga swi n’wayana swi heta swi hlota makondlo swin’we

TSHIVENḒA
Translation:  tendela zwo fhiraho zwi fhire
Proverb: i ri u tshi ndzima, u mphele ṅwana