Genuine assurance

(Thomas Brooks, "The Crown and Glory of Christianity,
 or, HOLINESS, the Only Way to Happiness", 1662)

Genuine holiness will yield you a heaven hereafter; but
genuine assurance will yield you a heaven here. He
who has holiness and knows it, shall have two heavens
—a heaven of joy, comfort, peace, contentment, and
assurance here—and a heaven of happiness and
blessedness hereafter.

Genuine assurance will be a spring of joy and comfort                       
in you. It will make heavy afflictions light, long afflictions
short, and bitter afflictions sweet. It will make you frequent,
fervent, constant, and abundant in the work of the Lord. It
will strengthen your faith, raise your hope, inflame your love,
increase your patience, and brighten your zeal. It will make
every mercy sweet, every duty sweet, every ordinance sweet,
and every providence sweet. It will rid you of all your sinful
fears and cares. It will give you ease under every burden,
and make death more desirable than life. It will make you
more strong to resist temptation, more victorious over
opposition, and more silent in every difficult condition.

Genuine assurance will turn . . .
  every winter night into a summer's day,
  every cross into a crown, and
  every wilderness into a paradise.

Genuine assurance will be . . .
  a sword to defend you,
  a staff to support you,
  a cordial to strengthen you,
  a medicine to heal you, and
  a star to lead you.

Well, remember this—next to a man's being saved, it is the
greatest mercy in this world—to know that he is saved.