The following are quotes from the Bhagavad Gita (Song of God), which was written in Sanskrit approximately between the fifth and second century B.C. After all these centuries, the ancient Wisdom from the Bhagavad Gita is still relevant and useful in our modern times.
Still your mind in me, still yourself in me, and without a doubt you shall be united with me, Lord of Love, dwelling in your heart.
Better indeed is knowledge than mechanical practice. Better than knowledge is meditation. But better still is surrender of attachment to results, because there follows immediate peace.
The soul who meditates on the Self is content to serve the Self and rests satisfied within the Self; there remains nothing more for him to accomplish
When meditation is mastered, the mind is unwavering like the flame of a lamp in a windless place.
Hell has three gates: lust, anger and greed
Which is as poison in the beginning, but is like nectar in the end; that is declared to be good pleasure, born from the serenity of one’s own mind. That which is like nectar in the beginning from the connection of the sense-object with the senses, but is as poison in the end, is held to be of passion.
On action alone be thy interest, never on its fruits. Let not the fruits of action be thy motive, nor be thy attachment to inaction.
Those who consciousness is unified abandon all attachment to the results of action and attain supreme peace. But those whose desires are fragmented, who are selfishly attached to the results of their work, are bound in everything they do.