Today

There is not anything one should not be ready to tolerate, and there is nobody whom one should not forgive.
Never doubt those whom you trust; never hate those whom you love; never cast down those whom you once raise in your estimation.
Wish to make friends with everyone you meet; make an effort to gain the friendship of those you find difficult ... No one is either higher or lower than oneself.
In all sources that fulfill one's need, one may see one source, God, the only source; and in admiring and in bowing before and in loving anyone, one may consider one is doing it to God.
In sorrow one may look to God, and in joy one may thank Him.
One does not bemoan the past, nor worry about the future; one tries only to make the best of today.
One should know no failure, for even in a fall there is a stepping-stone to rise.
In Fitzgerald's translation of Omar Khayyam:

'O my Beloved, fill the cup that clears today of past regrets and future fears. Why, tomorrow I may be myself, with yesterday's sev'n thousand years!'

By this he means:
Make the best of this moment; it is now that you can clearly see eternity, if you live in this moment. But if you keep the world of the past or the world of the future before you, you do not live in eternity but in a limited world.
In other words, live neither in the past nor in the future, but in eternity.
It is now that we should try to discover that happiness which is to be found in the freedom of the soul. -- Pir-o-Murshid Inayat Khan

Do not bemoan the past,
do not worry about the future,
but try to make the best of today.