All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Sacrificing an animal (ritual slaughtering) is one of the greatest acts of worship, and according to some scholars, it is the greatest of financial acts of worship.
In many verses in the Quran, Allah couples slaughtering along with the prayer, like in the following Sayings of Allah (which mean):
• {So pray to your Lord and sacrifice [to Him alone]..} [Quran 108:2]
• {Say, "Indeed, my prayer, my rites of sacrifice, my living and my dying are for Allah, Lord of the worlds.} [Quran 6:162]
The prayer and sacrificing an animal are evidence that one needs Allah and thinks good of Him. They are evidence of the strength of certainty in the Promise and Favor of Allah. Contrarily to the arrogant people who claim that they do not need Allah; so they do not pray and they do not slaughter because they fear poverty; hence, they do not help the poor and they think bad of their Lord.
Slaughtering is also from the religion of Ibraaheem (Abraham) whom we are ordered to follow. It reminds us of the story when Allah ordered him to sacrifice his son Ismaa’eel (Ishmael) and other lessons in that story. Allah informed us that He granted the cattle for people so that they would mention His Name (when they slaughter the animal); Allah Says (what means):
• {And the camels and cattle We have appointed for you as among the symbols [i.e. rites] of Allah; for you therein is good. So mention the name of Allah upon them when lined up [for sacrifice]; and when they are [lifeless] on their sides, then eat from them and feed the needy [who does not seek aid] and the beggar. Thus have We subjected them to you that you may be grateful.} [Quran 22:36]
• {Their meat will not reach Allah, nor will their blood, but what reaches Him is piety from you.} [Quran 22:37]
The sacrifice is also a means of being grateful to Allah for His Blessings, benefitting the people by donating some of its meat in charity, feeding the poor from it, and other noble wisdoms that are difficult to enumerate.
The ‘Aqeeqah (slaughtering upon receiving a newborn baby) is the same, and it is legislated for the same wisdom, in addition to it being a way of expressing gratitude to Allah for the blessing of the child.
As for the Jewish Passover, then we have nothing to do with it or to compare it to ‘Eid Al-Adh-ha.
Finally, you may advise that Christian to read the following Fataawa about Christianity: 30506, 10326, 90449 and 8210.
And refer to the following Fataawa that prove that Islam is the true religion, 88906, 86091, 16595, 173389, 9263 and 88051.
Allah knows best.