March 19, 2020 (Kitzur: When to Abstain?) References

Tanakh
Numbers 6:11
Proverbs 4:2
Ecclesiastes 7:16

Talmud
Taanit 11a
Nedarim 9:1 (Yerushalmi)

Kitzur Shulchan Arukh
Chapter 29: Moral and Ethical Rules Which a Person Should Adopt