Samadhi

When we teach people in the world to cultivate samadhi, they must first of all cut away the mind of lust. Therefore, Ananda, if cultivators of dhyana-samadhi do not eliminate lust, they will be like someone who cooks sand in the hope of getting rice. After hundreds of thousands of aeons it will just be hot sand. Why？ It wasn't rice to start with, it was only sand (Surangama Sutra 6 Verse 13-14)

Once your nature is in samadhi and the demons are subdued,
You'll be happy every day.
If false thoughts do not arise,
Everywhere you are at peace. (Flower Adornment Sutra Chapter 11 Verse 132)

Samadhi is "a concentrated, self collected, intent state of mind and meditation, which concomiant with the right living, is a necessary condition to the attainment of higher wisdom and emancipation" (Rhy Davids from Pali-English Dictionary)

"What is the meaning of proper concentration and proper reception (Samadhi)? Proper concentration is the state of absorption where the mind is brought into focus which is proper and true and right, not biased or deviant. Proper reception means all that 'comes in' - what you receive at that point-is right and appropriate. But you have to do the cultivation yourself. You can't rely on the Buddhas and Bodhisattvas and expect them to give it to you. If you do the work, then the results are naturally yours." (Entering the Dharma Realm Chap VII, Verse 60)

There are three distinct senses in which the word Samadhi is used:
1) proper concentration, which is necessary, preliminary to meditative states proper;
2) a general characteristic of the formal levels of meditational development which are entered through one pointedness of mind;
3) enlightened meditational states.

For someone who has the power of samadhi,

Even when Mount Tai topples over, I'm not scared.
Why? Its toppling over is the same as of it hadn't toppled over.
When a pretty girl appears before me, I'm not moved.
Face to face with her,
it's as if I wasn't
(Entering The Dharma Realm Chapter 1, Verse 12)