A parent who still criticizes you
The Simile of the Saw lists five ways anyone may criticize you — timely or not, true or false, gentle or harsh, useful or harmful, kind or hostile at heart — and trains the listener to meet every one of them with a heart of love toward that particular person. That is not the same as agreeing, and it is not the same as continuing to take it in. The argument you carry on in your head afterward runs after a past that is already gone, which one short set of verses advises against, and resentment has five named ways to be put down. The same canon says parents are hard to repay for raising you; it says nothing that obliges you to keep listening to contempt. The passages here cannot make a parent stop, and they do not say how often you must call.
What the suttas say
Mendicants, there are these five ways in which others might criticize you. Their speech may be timely or untimely, true or false, gentle or harsh, beneficial or harmful, from a heart of love or from secret hate.
How to receive speech, including unfair speech.
MN 21:11.1–11.6 · The Simile of the Saw
Pañcime, bhikkhave, vacanapathā yehi vo pare vadamānā vadeyyuṁ— kālena vā akālena vā; bhūtena vā abhūtena vā; saṇhena vā pharusena vā; atthasaṁhitena vā anatthasaṁhitena vā; mettacittā vā dosantarā vā.
Even as a mother would protect with her life her child, her only child, so too for all creatures unfold a boundless heart. With love for the whole world, unfold a boundless heart: above, below, all round, unconstricted, without enmity or foe. When standing, walking, sitting, or lying down while yet unweary, keep this ever in mind; for this, they say, is a divine meditation in this life.
The Metta Sutta's central image, in the canon's own words.
Where this stops: The verses are an ideal of the practitioner; the opening lines describing a skilled and honest person are a description, not a prerequisite for beginning. Never use it to quiet anger that has something to say, and never present it as a recitation that protects anyone. The mother guarding her only child is not for someone after a pregnancy loss.
Kp 9:7.1–9.4 · The Discourse on Love
Mātā yathā niyaṁ puttam Āyusā ekaputtamanurakkhe; Evampi sabbabhūtesu, Mānasaṁ bhāvaye aparimāṇaṁ. Mettañca sabbalokasmi, Mānasaṁ bhāvaye aparimāṇaṁ; Uddhaṁ adho ca tiriyañca, Asambādhaṁ averamasapattaṁ. Tiṭṭhaṁ caraṁ nisinno va, Sayāno yāvatāssa vitamiddho; Etaṁ satiṁ adhiṭṭheyya, Brahmametaṁ vihāramidhamāhu.
Regard one who sees your faults as a guide to a hidden treasure. Stay close to one so intelligent and astute who curbs you when you need it. Sticking close to such an impartial person, things get better, not worse.
Accurate criticism as something worth seeking out — the critic as a guide to treasure.
Where this stops: The verse is about an intelligent and impartial critic; it does not ask anyone to treat contempt or cruelty as treasure.
Dhp 76:1–6 · 6. The Astute
Nidhīnaṁva pavattāraṁ, yaṁ passe vajjadassinaṁ; Niggayhavādiṁ medhāviṁ, tādisaṁ paṇḍitaṁ bhaje; Tādisaṁ bhajamānassa, seyyo hoti na pāpiyo.
Don’t run back to the past, don’t anticipate the future. What’s past is left behind, the future has not arrived; and any present phenomenon you clearly discern in every case. The unfaltering, the unshakable: having known that, foster it.
The Bhaddekaratta verses — letting go of the chase after what is gone and what has not yet come, in favour of what is here.
Where this stops: The verses go on to urge effort today, since no one knows whether death comes tomorrow; they are about where attention goes, not a dismissal of planning or of a past that still needs repair.
MN 131:3.1–3.8 · One Fine Night
Atītaṁ nānvāgameyya, nappaṭikaṅkhe anāgataṁ; Yadatītaṁ pahīnaṁ taṁ, appattañca anāgataṁ. Paccuppannañca yo dhammaṁ, Tattha tattha vipassati; Asaṁhīraṁ asaṅkuppaṁ, Taṁ vidvā manubrūhaye.
We will meditate spreading a heart of love to that individual. And with them as a basis, we will meditate spreading a heart full of love to everyone in the world—abundant, expansive, limitless, free of enmity and ill will.’
Mettā starts with the specific person who spoke harshly, then widens; the order matters.
Where this stops: A training for one's own mind under hard speech. It is never a reason to stay where someone keeps speaking to you with contempt or threats, and never a ruling on whether to leave.
MN 21:11.14 · The Simile of the Saw
Tañca puggalaṁ mettāsahagatena cetasā pharitvā viharissāma, tadārammaṇañca sabbāvantaṁ lokaṁ mettāsahagatena cittena vipulena mahaggatena appamāṇena averena abyābajjhena pharitvā viharissāmā’ti.