Exodus 12:15
13 The blood will be a sign for you on the houses where you are, so that when I see the blood I will pass over you, and this plague will not fall on you to destroy you when I attack the land of Egypt. 14 “‘This day will become a memorial for you, and you will celebrate it as a festival to the Lord—you will celebrate it perpetually as a lasting ordinance. 15 For seven days you must eat bread made without yeast. Surely on the first day you must put away yeast from your houses because anyone who eats bread made with yeast from the first day to the seventh day will be cut off from Israel. 16 “‘On the first day there will be a holy convocation, and on the seventh day there will be a holy convocation for you. You must do no work of any kind on them, only what every person will eat—that alone may be prepared for you. 17 So you will keep the Feast of Unleavened Bread, because on this very day I brought your regiments out from the land of Egypt, and so you must keep this day perpetually as a lasting ordinance.
Psalms of Solomon 3:7
5 The righteous stumble and still prove the Lord is right; if they fall, they expect God to help them; they look to the source of their salvation. 6 The confidence of the righteous comes from God their savior. Repeated sin is not found in the home of the righteous. 7 The righteous thoroughly examine their homes to remove their unintentional offences. 8 They atone for sins of ignorance by fasting and humility and the Lord will cleanse every devout person and their household. 9 The sinners stumble and curse their life, the day of their birth and their mother's labor pain.
Notes and References
"... The idea of moral progress also starts to make more of an appearance in other works from the late Second Temple period ... There is sometimes also an emphasis on ascetic practices that will purify one’s character. Thus in Psalms of Solomon 3 we read, ‘The righteous constantly searches his house to remove his unintentional sin’ (a possible allusion to seeking out leaven before Passover) ... Fasting, prayer, and almsgiving hone the person and make him or her better ..."
Barton, John Ethics in Ancient Israel (p. 163) Oxford University Press, 2014