بِسْمِ اللّهِ الرَّحْمـَنِ الرَّحِيمِ
Abusa'id Abolkhayr or Abū-Sa'īd Abul-Khayr (ابوسعید ابوالخیر) has one of his quatrains (Ruba'i) which I saw hanging to the left after the entrance to the tomb of Maulana Rumi, and it offers tremendous hope for sinners like us:
باز آ باز آ هر آنچه هستی باز آ
Come back, Come back
Whoever you are
Whoever you are
گر کافر و گبر و بتپرستی باز آ
An infidel, a fire-worshipper or an idolator
Come back.
Come back.
این درگه ما درگه نومیدی نیست
This dargah (portal/shrine) is not the place of losing hope
صد بار اگر توبه شکستی باز آ
Even if you have broken your penitence hundreds of times
Come back.
Those who are interested in hearing the original Farsi can look at this beautiful recitation by one of my friends:
Or another one by Masood Khalili on Youtube: