Increase in Takbeer, Tahleel and Tahmeed in these days and Revive the Sunnah
It is Sunnah to recite Takbeer at any time during the first ten days of Dhul-Hijjah and all the days of Tashreeq, starting from the beginning of the month of Dhul-Hijjah (i.e., from sunset on the last day of Dhul-Qa’dah) until the end of the days of al-Tashreeq. The unrestricted Takbir can be recited at any time from the beginning of Dhul-Hijjah until the last Day of Tashriq. The restricted Takbir should be recited after the Obligatory Daily Prayers starting from the Fajr (Dawn) Prayer of the Day of `Arafah until the ‘Asr Prayer on the last Day of Tashriq.
Abdullaah ibn ‘Umar (may Allaah be pleased with him and his father) reported that the Prophet (Salla Allaahu ‘alaihi wa sallam) said: “There are no days greater in the sight of Allaah and in which righteous deeds are more beloved to Him than these ten days, so during this time recite a great deal of Tahleel (“La ilaaha ill-Allaah“), Takbeer and Tahmeed.” [Reported by Ahmad and authenticated by Ahmad Shaakir – Its chain is correct]
When Ibn ‘Umar and Abu Hurairah (Radia-Allaahu ‘anhuma) went to the market places during the ten days of Dhul-Hijjah they would say the Takbeer (loudly). The people would say the Takbeer accordingly and Mina would shake with their Takbeer. ‘Umar (Radia-Allaahu ‘anhu) used to say the Takbeer while he was in his house and the people in the Masjid hearing his Takbeer would say it accordingly.*
Note: Women should say the Takbeer in their houses and say it loudly, in order to revive acting upon this Sunnah, and to teach this rite to their children.
* – It should be noted as well it is not prescribed from the Sunnah to say the Takbeer/Dhikr in a unison form.
A question was put forth to The Permanent Committee for Scholarly Research and Ifta’ in Saudi Arabia, if this act of saying Takbir in a unison form was a Sunnah or a Bid‘ah (innovation in religion) and was answered:
A: Collective Takbir is Bid‘ah, as there is no evidence to support it from the Qur’an or the Sunnah. The Prophet (peace be upon him) said, “Anyone who does an action which is not in accordance with this matter of ours (Islam), will have it rejected.”….
Read the rest of the Fatwa here: alifta.com