Hasan al-Basri (:rahim:) used to say:

“If you are not able to stand in the night prayer, nor able to fast during the day, then know that you are deprived and you have been shackled by your mistakes and sins.” – Ibn Al-Jawzee

Hasan al-Basri (:rahim:) said:

“O’ son of Adam! Abandoning the sins are easier than seeking repentance!” – Az-Zuhd of Ahmad ibn Hanbal