1. The Temple - The temple was a religious place where people met with the representatives of God, the priests. The indwelling presence of God was in the temple.  

2. The Synagogue - The synagogue was another religious place where God's people met with each other, with the central role of studying and discussing the Scriptures, praying together, and having fellowship with each other. 

3. The Ekklesia - The ekklesia, on the other hand, was a governmental institution—a body of people assembled to conduct governmental business. It represented a secular institution and a governmental system. [In essence,] it was a decision-making, society-impacting, people institution. The ekklesia was ultimately an assembly of people deputized by the Roman emperor to introduce and implement the laws of the empire. The function of that ekklesia was to teach the language and culture of Rome. 

It is most revealing that Jesus did not say, "I Will build My Temple" or I will build My Synagogue"—the two premier Jewish religious institutions...

When the moment came to introduce His transformational agency, Jesus selected neither one. Instead, He announced that He would build His Ekklesia—choosing a term that, in the Roman empire in general and also in subjugated Israel, described a governmental institution... His intention all along was to co-opt an existing secular concept and impregnate it with His Kingdom DNA.  

The Lord did not discard everything that went on in the Temple or the synagogue, but assimilated significant components from both institutions into His Ekklesia. From the Temple He kept the indwelling presence of God, and from the synagogue the central role of the Scriptures and the fellowship of its members. 

Where the Temple and the synagogue differ with Jesus' Ekklesia, however, is in the areas of constitution, location, and mobility. The Temple and the synagogue were static institutions that functioned in buildings that members had to go to on specified occasions, whereas...  

The Ekklesia was a building-less, mobile, people movement operating 24/7 in the marketplace to impact everybody and everything. 

It was designed as the vehicle to inject the leaven of the Kingdom of God into the dough of society so that first people, and then cities and eventually nations, would be discipled... Jesus designed His Ekklesia to make its presence, power and culture [the culture of heaven] known, but with a revolutionary caveat that gave it the upper hand: It would have the authority to legislate in both the visible and invisible realms so that the Gates of Hades could not prevail in either realm.  

18 "And I tell you that you are Peter, and on this rock I will build my church [Ekklesia], and the gates of Hades will not overcome it. 19 I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” - Matthew 16:18-19 ESV

15 “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. 16 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. 17 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. 18 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. 19 Again I say to you, if two of you agree on earth about anything they ask, it will be done for them by my Father in heaven. 20 For where two or three are gathered in my name, there am I among them.” - Matthew 18:15-20 ESV

18 Then Jesus came to them and said, “All authority in heaven and on earth has been given to me. 19 Therefore go [as you are going] and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.” - Matthew 28:18-20 NIV