On the first day of the Festival of Unleavened Bread, when it was customary to sacrifice the Passover lamb, Jesus’ disciples asked him, “Where do you want us to go and make preparations for you to eat the Passover?” (Mark 14:12)
The bible does not say Jesus ate lamb. It says he observed Passover with his disciples. The only foods mentioned were bread and the fruit of the vine. Jesus said he is the unblemished Lamb of God and to therefore eat his flesh. The only gospel that mentions lamb is Mark:14:12 where it says the Passover holiday is a time when it is customary to sacrifice a lamb. It says this because the gospel of Mark was written for a gentile audience unfamiliar with Jewish customs.
The Sadducees were in control of the temple at the time of Jesus, and Jesus was very critical of them and their religious practices (Matthew 16:1-4). The temple is where animal sacrifices took place. The Nazarene sect (sometimes called the Essenes) did not believe in animal sacrifices, instead believing the word of the prophets (Isaiah, Jeremiah, Hosea, Micah, Zechariah, Malachi, and Habakkuk) that say God wanted mercy and faithful stewardship instead of animal sacrifices. This Jewish sect observed Passover with bread and grape juice (the two foot items specifically mentioned during the meal Jesus shared with his disciples), and without animal flesh.
It’s unclear historically to what extent Jesus associated with the Nazarene sect, but it is clear from the gospel accounts that he most definitely did not agree with the Sadducees and their interpretations of scripture. In fact, his death was the direct result of him overturning the tables in their temple court and disrupting their business of selling animals for profit to be slaughtered in the name of God (Matthew 21:12-17; Mark 11:15-19; Luke 19:45-48; John 2:13-16). In contrast, there is no record of Jesus saying anything negative about the Nazarene sect and their religious observances.
Regardless of whether you believe Jesus ate lamb, the main takeaway should be that Jesus walked to his own death alongside the animals being slaughtered (Isaiah 53:7), prayed for the forgiveness of those slaughtering him in the name of God (Luke 23:34), and prayed that the world would turn from its evil ways and return to God’s ways of love (Matthew 6:10; John 15:12). We should act in accordance with Jesus’ character of mercy and his prayer for the peaceable kingdom where there will be no more bloodshed (Revelation 21:4) rather than searching the scriptures for justification to serve the desires of the flesh (Galatians 5:17) as the Pharisees did (John 5:39-40; Matthew 23:14).