It might surprise people to know that Jesus didn’t talk about church very much. While Jesus does spend a lot of time talking about what I would call “Kingdom oriented relationships and practices,” in all four Gospels, Jesus only mentions church (Greek ekklesia) explicitly in two passages, and both are in Matthew.
In Matthew 16 Jesus responds to Peter’s confession that he is the Christ by saying:
“Blessed are you, Simon son of Jonah! For flesh and blood has not revealed this to you, but my Father in heaven. And I tell you, you are Peter, and on this rock I will build my church [ekklesia], and the gates of Hades will not prevail against it. I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” (Matthew 16.17–19 NRSV)
Then later in Matthew 18 at the end of instruction on how to deal with someone who has “sinned against you”, Jesus says:
“If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother. But if he does not listen, take one or two others along with you, that every charge may be established by the evidence of two or three witnesses. If he refuses to listen to them, tell it to the church [ekklesia]. And if he refuses to listen even to the church [ekklesia], let him be to you as a Gentile and a tax collector. Truly, I say to you, whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.” (Matthew 18.15–18 ESV)