Question: How to strengthen the mind and stay focused on our goals after having a hard time with the outer world.

Thank you for writing with your question.

In the Bhagavad Gita Krishna says:

vyavasayatmika buddhir
ekeha kuru-nandana
bahu-shaka hy anantash ca
buddhayo ‘vyavasayinam

“Those on the path of spiritual advancement are resolute in purpose, and their aim is one. The intelligence of those who are irresolute is many-branched.”

We must focus our intelligence on one aim, otherwise all of our endeavours will result in failure. One whose mind is branched in many directions fails to concentrate on anything and is simply left in confusion. The nature of the mind is to drift. We must learn to control the mind with our spiritual intelligence, otherwise the mind will be the cause of our own bondage. In the Gita Krishna describes that the mind can either be our best friend or our worst enemy:

bandhur atmatmanas tasya
yenatmaivatmana jitah
anatmanas tu shatrutve
vartetatmaiva shatru-vat

“For him who has conquered the mind, the mind is the best of friends; but for one who has failed to do so, his mind will remain the greatest enemy.”

The mind is the repository of all sensual perception. Through our five knowledge acquiring senses we experience the world, and the resultant experience is transmitted to the mind, where it is classified as either enjoyment or distress. The uncontrolled mind begins to dwell on the desires and fears created by these experiences. The result is a whirlpool of thoughts making it unable for us to think,
concentrate, and focus our selves. Krishna says:

nasti buddhir ayuktasya
na cayuktasya bhavana
na cabhavayatah shantir
ashantasya kutah sukham

“One who is not connected with the Supreme can have neither transcendental intelligence nor a steady mind, without which there is no possibility of peace. And how can there be any happiness without peace?”

Thus it is necessary to develop a link with the Supreme. This process is known technically as yoga. Either through bhakti-yoga, jnana-yoga, or karma yoga one must link oneself to the Supreme, for this will give one spiritual intelligence. With spiritual intelligence it will be possible to control the mind. With a controlled mind it will be possible to attain peace. And with peace, the internal happiness will become manifested to oneself.