It is narrated from Amr bin Dinar that he heard Sayyiduna Ibn Abbas (may Allah be pleased with them both) reciting the takbeers (Allahu Akbar, Allahu Akbar) on the days of Eid. Amr (bin Dinar) said: I do not know which of the two matters he intended. The statement of Allah Almighty: "When you have completed the rites of Hajj, then remember Allah." Or His statement: "And remember Allah during the appointed number of days."
Hadith Referenceمسند اسحاق بن راهويه / كتاب العيدين / 229
Benefits: Reciting the takbirs on the days of the two Eids is Sunnah. Likewise, it is also Sunnah during the days of Tashreeq, as Allah the Exalted says: ﴿وَاذْکُرُوااللّٰهَفِیْٓاَیَّامٍمَّعْدُوْدٰتٍ﴾ () .... “And remember Allah during the appointed number of days.” Sayyiduna Ibn Abbas (radi Allahu anhuma) said: By “the appointed number of days” (ayyam ma’dudat) is meant the days of Tashreeq. (Bukhari, no. 969) Various wordings of the takbirs are authentically reported from the noble Companions (radi Allahu anhum). In the narration from Sayyiduna Salman (radi Allahu anhu), the wording is: ((Allahu Akbar, Allahu Akbar, Allahu Akbar Kabiran.)) (Sunan al-Kubra al-Bayhaqi: 3/316; Nayl al-Awtar: 2/621) In the hadith narrated from Sayyiduna Ibn Abbas (radi Allahu anhuma), the wording is: ((Allahu Akbar Kabiran, Allahu Akbar Kabiran, Allahu Akbar wa Ajal, Allahu Akbar wa lillahil-hamd.)) (Musannaf Ibn Abi Shaybah: 1/489)