1Then a certain bhikkhu approached the Blessed One, paid homage to him, sat down to one side, and said to him: "Here, venerable sir, while I was alone in seclusion, a reflection arose in my mind thus: ‘Three feeling have been spoken of by the Blessed One: pleasant feeling, painful feeling, neither-painful-nor-pleasant feeling. These three feelings have been spoken of by the Blessed One. But the Blessed One has said: "Whatever is felt is included in suffering." Now with reference to what was this stated by the Blessed One?’"

2"Good, good, bhikkhu! These three feelings have been spoken of by me: pleasant feeling, painful feeling, neither-painful-nor-pleasant feeling. These three feelings have been spoken of by me. And I have also said: ‘Whatever is felt is included in suffering.’ That has been stated by me with reference to the impermanence of formations. That has been stated by me with reference to formations being subject to destruction … to formations being subject to vanishing … to formations being subject to fading away sn.iv.217 … to formations being subject to cessation … to formations being subject to change. [n.241] Spk: The impermanence of formations is itself the impermanence of feelings, and this impermanence is death. There is no suffering worse than death: with this intention it is said, "All feeling is suffering."
On this maxim, see too SN12.32 and MN136 etc. Spk's explanation is not very cogent. The real reason all feeling is suffering is because all feeling is impermanent and thus cannot provide stable happiness and security.

"Then, bhikkhu, I have also taught the successive cessation of formations. [n.242] Anupubbasaṅkhārānaṃ nirodho. Spk: This is introduced to show, "I describe not only the cessation of feelings, but also the cessation of these (other) states." Below, "subsiding" (vīpasama) and "tranquillization" (passaddhi) are spoken of in conformity with the inclinations of those to be enlightened by the teaching. For one who has attained the first jhāna, speech has ceased. For one who has attained the second jhāna, thought and examination have ceased. For one who has attained the third jhāna, rapture has ceased. For one who has attained the fourth jhāna, in-breathing and out-breathing have ceased. For one who has attained the base of the infinity of space, the perception of form has ceased. For one who has attained the base of the infinity of consciousness, the perception pertaining to the base of the infinity of space has ceased. For one who has attained the base of nothingness, the perception pertaining to the base of the infinity of consciousness has ceased. For one who has attained the base of neither-perception-nor-nonperception, the perception pertaining to the base of nothingness has ceased. For one who has attained the cessation of perception and feeling, perception and feeling have ceased. For a bhikkhu whose taints are destroyed, lust has ceased, hatred has ceased, delusion has ceased.

"Then, bhikkhu, I have also taught the successive subsiding of formations. For one who has attained the first jhāna speech has subsided … . For one who has attained the cessation of perception and feeling, perception and feeling have subsided. For a bhikkhu whose taints are destroyed, lust has subsided, hatred has subsided, delusion has subsided.

"There are, bhikkhu, these six kinds of tranquillization. For one who has attained the first jhāna, speech has been tranquillized. For one who has attained the second jhāna, thought and examination have been tranquillized. For one who has attained the third jhāna, rapture has been tranquillized. For one who has attained the fourth jhāna, in-breathing and out-breathing have been tranquillized. sn.iv.218 For one who has attained the cessation of perception and feeling, perception and feeling have been tranquillized. For a bhikkhu whose taints are destroyed, lust has been tranquillized, hatred has been tranquillized, delusion has been tranquillized."

1Atha kho aññataro bhikkhu yena bhagavā tenupasaṅkami; upasaṅkamitvā bhagavantaṁ abhivādetvā ekamantaṁ nisīdi. Ekamantaṁ nisinno kho so bhikkhu bhagavantaṁ etadavoca: "idha mayhaṁ, bhante, rahogatassa paṭisallīnassa evaṁ cetaso parivitakko udapādi – tisso vedanā vuttā bhagavatā. Sukhā vedanā, dukkhā vedanā, adukkhamasukhā vedanā – imā tisso vedanā vuttā bhagavatā. Vuttaṁ kho panetaṁ bhagavatā: ‘Yaṁ kiñci vedayitaṁ taṁ dukkhasmin’ti. Kiṁ nu kho etaṁ bhagavatā sandhāya bhāsitaṁ: ‘Yaṁ kiñci vedayitaṁ taṁ dukkhasmin’"ti?

2"Sādhu sādhu, bhikkhu. Tisso imā, bhikkhu, vedanā vuttā mayā. Sukhā vedanā, dukkhā vedanā, adukkhamasukhā vedanā – imā tisso vedanā vuttā mayā. Vuttaṁ kho panetaṁ, bhikkhu, mayā: ‘Yaṁ kiñci vedayitaṁ, taṁ dukkhasmin’ti. Taṁ kho panetaṁ, bhikkhu, mayā saṅkhārānaṁyeva aniccataṁ sandhāya bhāsitaṁ: ‘Yaṁ kiñci vedayitaṁ taṁ dukkhasmin’ti. Taṁ kho panetaṁ, bhikkhu, mayā saṅkhārānaṁyeva khayadhammataṁ … pe … vayadhammataṁ … pe … virāgadhammataṁ … pe … nirodhadhammataṁ … pe … vipariṇāmadhammataṁ sandhāya bhāsitaṁ: ‘Yaṁ kiñci vedayitaṁ taṁ dukkhasmin’ti.

Atha kho pana, bhikkhu, mayā anupubbasaṅkhārānaṁ nirodho akkhāto. Paṭhamaṁ jhānaṁ samāpannassa vācā niruddhā hoti. Dutiyaṁ jhānaṁ samāpannassa vitakkavicārā niruddhā honti. Tatiyaṁ jhānaṁ samāpannassa pīti niruddhā hoti. Catutthaṁ jhānaṁ samāpannassa assāsapassāsā niruddhā honti. Ākāsānañcāyatanaṁ samāpannassa rūpasaññā niruddhā hoti. Viññāṇañcāyatanaṁ samāpannassa ākāsānañcāyatanasaññā niruddhā hoti. Ākiñcaññāyatanaṁ samāpannassa viññāṇañcāyatanasaññā niruddhā hoti. Nevasaññānāsaññāyatanaṁ samāpannassa ākiñcaññāyatanasaññā niruddhā hoti. Saññāvedayitanirodhaṁ samāpannassa saññā ca vedanā ca niruddhā honti. Khīṇāsavassa bhikkhuno rāgo niruddho hoti, doso niruddho hoti, moho niruddho hoti.

Atha kho, bhikkhu, mayā anupubbasaṅkhārānaṁ vūpasamo akkhāto. Paṭhamaṁ jhānaṁ samāpannassa vācā vūpasantā hoti. Dutiyaṁ jhānaṁ samāpannassa vitakkavicārā vūpasantā honti … pe … saññāvedayitanirodhaṁ samāpannassa saññā ca vedanā ca vūpasantā honti. Khīṇāsavassa bhikkhuno rāgo vūpasanto hoti, doso vūpasanto hoti, moho vūpasanto hoti.

Chayimā, bhikkhu, passaddhiyo. Paṭhamaṁ jhānaṁ samāpannassa vācā paṭippassaddhā hoti. Dutiyaṁ jhānaṁ samāpannassa vitakkavicārā paṭippassaddhā honti. Tatiyaṁ jhānaṁ samāpannassa pīti paṭippassaddhā hoti. Catutthaṁ jhānaṁ samāpannassa assāsapassāsā paṭippassaddhā honti. Saññāvedayitanirodhaṁ samāpannassa saññā ca vedanā ca paṭippassaddhā honti. Khīṇāsavassa bhikkhuno rāgo paṭippassaddho hoti, doso paṭippassaddho hoti, moho paṭippassaddho hotī"ti.

Paṭhamaṁ.