To develop a peaceful state of mind

"Watch your manner of speech if you wish
to develop a peaceful state of mind.
Start each day by affirming peaceful, contented and
happy attitudes and your days will tend to be pleasant and successful."
- Norman Vincent Peale

"And the peace of God, which surpasses all comprehension,
will guard your hearts and your minds in Christ Jesus.
Finally, brethren, whatever is true, whatever is honorable,
whatever is right, whatever is pure, whatever is lovely,
whatever is of good repute, if there is any excellence
and if anything worthy of praise, dwell on these things."
Philippians 4:7-8

World full of suffering

“Although the world is full of suffering,
it is also full of the overcoming of it.”
- Helen Keller

"I have told you these things,
so that in me you may have peace.
In this world you will have trouble.
But take heart! I have overcome the world."
John 16:33