Sincerity...

Sincerity is the jewel that forms in the shell of the heart.

Bowl of Saki, by Hazrat Inayat Khan

Commentary by Pir-o-Murshid Inayat Khan:

Very few realize what power sincerity carries. A false man, however physically
strong he is or however great is his willpower, is kept down by his falsehood;
it never allows him to rise. It eats into him because it is rust. Those who have
done great things in life, in whatever walk of life it be, have done them by the
power of truth, the power of sincerity.

Sincerity is the principal thing in life. Youth is the age which is most
attracted to superficiality. That is the reason why many youths adopt an
artificial manner of thought, speech and action, which is very undesirable and
does not benefit their life. It is important to inculcate sincerity in the
character of the youth. To give a youth a love of sincerity is extremely useful,
for the power of sincerity can work miracles.

The more sincerity is developed, the greater share of truth you will have. And
however much sincerity a person may have, there is always a gap to fill, for we
live in the midst of falsehood, and we are always apt to be carried away by this
world of falsehood. Therefore we must never think we are sincere enough, and we
must always be on our guard against influences which may carry us away from that
sincerity which is the bridge between ourselves and our ideal. No study, no
meditation is more helpful than sincerity itself.