CauldronsOkkhāsutta

At Sāvatthī.Sāvatthiyaṁ viharati.

“Mendicants, suppose one person was to give a gift of a hundred cauldrons of rice in the morning, at midday, and in the evening. And someone else was to develop a heart of love, even just as long as it takes to pull a cow’s udder. The latter would be more fruitful.“Yo, bhikkhave, pubbaṇhasamayaṁ okkhāsataṁ dānaṁ dadeyya, yo majjhanhikasamayaṁ okkhāsataṁ dānaṁ dadeyya, yo sāyanhasamayaṁ okkhāsataṁ dānaṁ dadeyya, yo vā pubbaṇhasamayaṁ antamaso gadduhanamattampi mettacittaṁ bhāveyya, yo vā majjhanhikasamayaṁ antamaso gadduhanamattampi mettacittaṁ bhāveyya, yo vā sāyanhasamayaṁ antamaso gadduhanamattampi mettacittaṁ bhāveyya, idaṁ tato mahapphalataraṁ.

So you should train like this:Tasmātiha, bhikkhave, evaṁ sikkhitabbaṁ: ‘We will develop the heart’s release by love. We’ll cultivate it, make it our vehicle and our basis, keep it up, consolidate it, and properly implement it.’‘mettā no cetovimutti bhāvitā bhavissati bahulīkatā yānīkatā vatthukatā anuṭṭhitā paricitā susamāraddhā’ti. That’s how you should train.”Evañhi vo, bhikkhave, sikkhitabban”ti.