This excerpt is taken from Sheikh Abu Hamza Abdul Khaliq Siddiqi's book Sahi Fazail-e-Amaal.
It is narrated from Sayyiduna Abu Hurairah (RA) that the Messenger of Allah (PBUH) said: "O Allah! Forgive those who shave their heads." The Companions said: O Messenger of Allah! Also pray for those who cut their hair. The Prophet (PBUH) said: O Allah! Forgive those who shave their heads. The Companions said: O Messenger of Allah! Also forgive those who cut their hair. The Prophet (PBUH) said: Also forgive those who cut their hair."
Reference: Sahih Bukhari, Book of Hajj, No: 1728.
Allah Almighty says: ﴿وَمَن يُعَظِّمْ شَعَائِرَ اللَّهِ فَإِنَّهَا مِن تَقْوَى الْقُلُوبِ﴾
"And whoever honors the rites of Allah - indeed, it is from the piety of hearts."
Reference: (22-Al-Hajj:32)
Abdullah bin Abbas (RA) says: "This means to respect the sacrifice and to make it substantial."
It is narrated from Sayyiduna Jabir bin Abdullah رضی اللہ عنہما that the Messenger of Allah صلی اللہ علیہ وآلہ وسلم said:
ماء زم زم لما شرب له.
"The water of Zamzam fulfills whatever purpose it is drunk for."
Reference: Sunan Ibn Majah, No: 3062 - Al-Arawa, No: 1123 -
Al-Albani رحمه اللہ has declared it "Sahih".