Vivekachudamani 336

बाह्ये निरुद्धे मनसः प्रसन्नता 

मनःप्रसादे परमात्मदर्शनम् । 

तस्मिन्सुदृष्टे भवबन्धनाशो 

बहिर्निरोधः पदवी विमुक्तेः ॥ ३३५ ॥ 

bāhye niruddhe manasaḥ prasannatā 

manaḥprasāde paramātmadarśanam | 

tasminsudṛṣṭe bhavabandhanāśo 

bahirnirodhaḥ padavī vimukteḥ || 

(Sankaracarya's Vivekachudamani 336) 

When the objective world is shut out, the mind becomes quiet and in the quiet mind arises the vision of the Supreme Personality of Godhead. When 'That‘ is perfectly realized, bondage to the world of becoming* is destroyed. Hence the cessation of the external world is the initial step on the path to liberation.

*Bhavabandhana means bondage of the world of becoming or conditioned existence. Hindu religion calls this world of becoming bhavasaagar, the ocean of repeated births and deaths. 

When our life is going very well, we will not have much time to think about the Supreme Personality of Godhead. When we are having extreme difficulties then we will seek the Lord who created us. Therefore we have to realize the real peacefulness and enjoyment can be given only by the Supreme Lord, not by material happiness.