The Blessed Buddha once
said:
Kāyamunim vacamunim,
manomunimanāsavam,
munim moneyyasampannam.
Ahu ninhātapāpakam.

Silenced in body, silenced in speech,
silenced in mind, without inner noise,
blessed with silence is the sage!
He is truly washed of all evil...
Itivuttaka 3.67

Calm is his mind.
Calm is his speech.
Calm is his behaviour.
So is the tranquillity;
So is the serenity;
of one freed by the insight
of right understanding...
Dhammapada
96

Sambādhe vāpi vindanti,
dhammam nibbānapattiyā
ye satim paccalatthamsu
sammā te susamāhitā.
Even when obstacles crowd
in,
then the path to Nibbāna can be won
by those who establish
awareness,
perfect focus and concentration.
Samyutta Nikāya 1.88