The Holy Prophet Muhammad (Sallallahu-Alayhi-Wasallam) said to Hazrat Abu-Bakr (Radhiyallahu-Anhu):
"For every people (nation) there is a feast, and this is our feast (Eid). (Bukhari, Muslim)
"Our feast" has a great meaning to Muslims because it tells us that our feasts are our own and derived from our Shari'ah alone. Feasts are usually based on religious traditions. It is very important that we demonstrate our celebrations with great joy and gathering together and observe them in such a way that distinguishes us from the Mushrikeen and Kuffar. We do not celebrate Christmas or any other festival and our thanks are given to Almighty Allah. The Holy Prophet (Sallallahu-Alayhi-Wasallam) has ordered us in numerous speeches to defy the Mushrikeen and Kuffar, and these two "Eids" are among what the Prophet (Sallallahu-Alayhi-Wasallam) said, after seeing that the people of Madinah had two feasts which they celebrated from before Islam:
"Almighty Allah has given you (Muslims) something better than those (feasts), "Eid-ul-Fitr and Eid-ul-Adha" (Abu-Dawood, Nasa'ee, Ahmad)
Eid-ul-Fitr comes after practising yet another pillar of Islam; Fasting in the month of Ramadhan. Zakah, another pillar of Islam, which is usually due on those days. Therefore it is not surprising that we show and demonstrate our feasts (Eids) with the most importance of the pillars of Islam after submitting the Shahadah; Salaah.
Because of these clear facts, Muslim scholars put great emphasis on the concept of being different from the Mushrikeen and Kuffar in our ceremonies. This is because ceremonies have a great effect over the human mind and behaviour. Being different in our ceremony means that we must not participate in the Mushrikeen's and Kuffar's ceremonies on their feasts too. Hazrat Umar (Radhiyallahu-Anhu) said:
"Do not learn the language of the Mushrikeen - nor enter the churches of the Mushrikeen on their festivals because the anger of Allah descends on them then." (Bayhaqi)
We Muslims may even fast on the Mushrikeens and Kuffars' feasts. The Prophet (Sallallahu-Alayhi-Wasallam) used to fast on Saturdays and Sundays, and when he was asked about this he said:
"They are two days of Mushrikeen's feasts, so I like to oppose them in their ceremonies.
To assess this concept of being different from the Mushrikeen and Kuffar, it is very important to say that in order to be different in our ceremonies in the way the Prophet (Sallallahu-Alayhi-Wasallam) wanted us to be, we must follow the Sunnah literally. That would give us the deeds of being true followers of the Holy Prophet Muhammad (Sallallahu-Alayhi-Wasallam).
Sunnah Acts of Eid