There are a lot of sites online that share Buddha quotes. Unfortunately, many of those quotes cannot be found in the Buddhist scriptures, let alone in the oldest Buddhist scriptures which are most likely to contain the Buddha’s word. In trying to find quotes about happiness in Buddhism, I naturally started with the oldest Buddhism. However, it is mostly concerned, not with people becoming happy, but with people overcoming suffering. Because the quotes are from more than 2000 years ago, I give my interpretation and summary after each quote.
For instance, in the Samyutta Nikaya V (199-200) the Buddha is reported to have said:
And what is the faculty of Wisdom? Herein the Ariyan disciple has wisdom. He is endowed with wisdom leading to the knowledge of rise and fall, Ariyan, piercing, leading rightly to the extinction of suffering.
[Rephrase in modern language, all my own: Wisdom is the knowledge of how things change, rise and fall. This insight will rightly lead to the extinction of sorrow and unhappiness.]
Many so called Buddha quotes are really summaries of long paragraphs in Buddhist texts. For instance Majjhima Nikaya I, 36-38, already condensed by Conze (p. 52, 53):
And what, monks, are the defilements of the mind? Greed and covetousness, malevolence, anger, malice, hypocrisy, spite, envy, stinginess, deceit, treachery, obstinacy, impetuosity, arrogance, pride, conceit, indolence. If a monk thinks and kn0ws that these are defilements of the mind and gets rid of them, he becomes possessed of unwavering confidence in the Buddha and thinks: ‘Thus indeed is he the Lord, Arahant, perfect Buddha … a Buddha a Lord.’ And he becomes possessed of unwavering confidence in the Dhamma and thinks: ‘Dhamma is well taught by the Lord, it is thoroughly seen here and now, it is timeless, inviting all to come-and-see, leading onwards [to nirvana], to be understood by the wise each for himself.’ And he becomes possessed of unwavering confidence in the Order and thinks: ‘The Lord’s Order of disciples is of good conduct, upright, of wise conduct, of dutiful conduct, that is to say the four pairs of men, the eight persons. [This refers to four stages on the Path, and those who have attained to the fruits of them] This Order of the Lord’s disciples is worthy of alms, hospitality, offerings and reverence, it is a matchless field of merit for the world.’
At this stage there is for him giving up, renouncing, rejecting, getting rid of, forsaking. When he thinks that he has unwavering confidence in the Buddha, Dhamma and the Order, he acquires knowledge of Dhamma and the delight connected with Dhamma; rapture is born from that delight; being rapturous, his body is impassible; this being so, joy is felt, and in consequence the mind is well concentrated.
This can be summed up as follows: Those who realize the defilements of the mind, will get rid of them. Getting rid of them they will become aware of the blessing of being free of them. Feeling that blessing, they will respect the Buddha and the Buddhist Sangha (the monks, the order) all the more. The result will be letting go of everything that can be let go of. They will realize their faith in the Buddha and the Sangha and this will lead to knowledge of Dhamma (Buddhist teachings) and the delight that comes from that. Rapture follows delight. Being in raptures, the body is no longer a source of distraction. This will lead to joy and a concentrated mind.
If that isn’t happiness, I don’t know what is… However it’s a very different kind of happiness than what can be found in ordinary life.
Pleasant feeling is one dead end, painful feeling the other, feeling that is neither painful nor pleasant is in the middle, craving is the sempstress, for craving sews one … (Anguttara Nikaya 3, 399-401 ; Conze p. 73)
In other words: neither painful feelings, nor pleasant ones are any help. Stay in the middle. Craving is the worst though: it binds one.