Happiness and unhappiness are not primarily created by the material world or the physical body. First and foremost, they are decisions of the mind.

by Yongey Mingyur Rinpoche

除此心外，见佛终不得也。佛是自心作得，因何离此心外觅佛？前佛后佛只言其心，心即是佛，佛即是心；心外无佛，佛外无心。若言心外有佛，佛在何处？……。若也不信，自诳无益。佛无过患，众生颠倒，不觉不知自心是佛。若知自心是佛，不应心外觅佛。佛不度佛，将心觅佛不识佛。但是外觅佛者，尽是不识自心是佛。亦不得将佛礼佛，不得将心念佛。佛不诵经，佛不持戒，佛不犯戒、佛无持犯，亦不造善恶。若欲觅佛，须是见性，见性即是佛。若不见性，念佛诵经持斋持戒亦无益处。

by 达摩大师

When Buddha himself was asked to summarize his teaching, he said,

Commit not a single unwholesome action,
Cultivate a wealth of virtue,
To tame this mind of ours,
This is the teaching of all the buddhas.

认清世间一切现象都是无常的事实，就能完成内心世界的真正平安。

 by 圣严法师

When sitting in meditation, say, “That’s not my business!” with every thought that comes by.

by Ajahn Chah

When the days become longer and there is more sunshine, the grass becomes fresh and, consequently, we feel very happy. On the other hand, in autumn, one leaf falls down and another leaf falls down. The beautiful plants become as if dead and we do not feel very happy. Why?

I think it is because deep down our human nature likes construction, and does not like destruction. Naturally, every action which is destructive is against human nature. Constructiveness is the human way. Therefore, I think that in terms of basic human feeling, violence is not good. Non-violence is the only way.

by Dalai Lama

三界:

(1) 欲界，即具有财欲、淫欲、情欲、色欲、食欲等有情所居之世界。上自第六他化自在天，中包括人界之四大洲，下至无间地狱等二十处；因男女参居，多诸染欲，故称欲界。

(2) 色界，色为变碍之义或示现之义，乃远离欲界淫、食二欲，而仍具有清净色质等有情所居之世界。此界在欲界之上，无有欲染，亦无女形，其众生皆由化生；其宫殿高大，系由色之化生，一切均殊妙精好。以其尚有色质，故称色界。此界依禅定之深浅粗妙而分四级，从初禅梵天，终至阿迦腻吒天，凡有十八天。

(3) 无色界，唯有受、想、行、识四心，而无物质之有情所住之世界。此界无一物质之物，亦无身体、宫殿、国土，唯以心识住于深妙之禅定，故称无色界。此界在色界之上，共有四天（空无边处天、识无边处天、无所有处天、非想非非想处天），又称四无色、四空处。

此三界之果报虽有优劣、苦乐等差别，但属迷界，系众生生死轮回之趣，故为圣者所厌弃。

<法华经·譬喻品>：三界无安，犹如火宅；众苦充满，甚可怖畏。
又《化城喻品》：能于三界狱，勉出诸众生。即劝三界诸有情莫以三界为安，当勤求解脱。

如来在世间，不言有与无；如来涅盘后，不言有与无。

by 印顺法师

不经一事不长一智，智慧是从人与事之间磨练出来的。

by 证严法师

人类的感官──眼、耳、鼻、舌、身、意，每天总是不断的向外去攀缘，对于外在的世界虚妄分别，因此产生了许多烦恼。如果我们能够一切返求自心，而不让此心随境而转，则不当看的不看，不当听的不听，不当说的不说。这就等于孔子说的：“非礼勿视，非礼勿听，非礼勿言，非礼勿动。

 by 星云法师

Anger needs no training to grow. On the relative level, compassion requires training. Relative compassion is like an illusion, but a good illusion that causes other illusions to dissipate.

by Yongey Mingyur Rinpoche

We work on ourselves in order to help others, but also we help others in order to work on ourselves.

by Pema Chodron