Be completely humble and gentle; be patient, bearing with one another in love. Make every effort to keep the unity of the Spirit through the bond of peace (Eph 4:2-3).

Note the phrase, “the unity of the Spirit.” There are all kinds of unity in which people gather and stay together, but we Christians are to keep “the unity of the Spirit.” Talking of unity, we are reminded of the story of the tower of Babel.

Now the whole world had one language and a common speech. As men moved eastward, they found a plain in Shinar and settled there (Gen 11:1-2).

These people moved eastward. After humans were driven out of the Garden of Eden, they moved eastward: Cain lived in the land, “east of Eden (4:16),” and the descendants of Shem in the post-diluvian period, especially, those of Joktan, lived “in the eastern hill country (10:30).” At this point, the sons of two brothers, Joktan and Peleg, were separated geographically and lived in different lands (cf. 10:25). This might be related to the fact that the more archaic east Semitic languages like Akkadian and Assyrian are distinguished from the relatively new west Semitic languages like Arabic, Hebrew and Aramaic.

They said to each other, "Come, let's make bricks and bake them thoroughly." They used brick instead of stone, and tar for mortar. Then they said, "Come, let us build ourselves a city, with a tower that reaches to the heavens, so that we may make a name for ourselves and not be scattered over the face of the whole earth (vv. 3-4)."

Note the use of the subject, 1st person plural “we,” in this passage: they, in unity, desired to build something that would help them to have more unity—“a city, with a tower that reaches to the heavens.”

But the Lord came down to see the city and the tower that the men were building. The Lord said, "If as one people speaking the same language they have begun to do this, then nothing they plan to do will be impossible for them. Come, let us go down and confuse their language so they will not understand each other (vv. 5-7)."

Did the tower really reach to the heavens? Ironically, God needed to come down to see the city and the tower, and it shows their foolishness in thinking that they could build such a tower. Compare the expression “one people speaking the same language” with the expressions found in the following passage:

There is one body and one Spirit-- just as you were called to one hope when you were called-- one Lord, one faith, one baptism; one God and Father of all, who is over all and through all and in all (Eph 5:8-10).

This “body” is the body of Christ, the church. Its head reaches to the heavens as Christ is seated at the right hand of the Father, and the body with its feet on the earth connects this world with God in heaven. Christ first “descended to the lower, earthly regions,” and “ascended higher than all the heavens.”

This is why it says: "When he ascended on high, he led captives in his train and gave gifts to men." What does "he ascended" mean except that he also descended to the lower, earthly regions? He who descended is the very one who ascended higher than all the heavens, in order to fill the whole universe (vv. 8-10).

God once stopped us from building the tower of Babel, but he himself built the body of Christ for us.

It was he who gave some to be apostles, some to be prophets, some to be evangelists, and some to be pastors and teachers, to prepare God's people for works of service, so that the body of Christ may be built up until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ (vv. 11-13).

Note the expressions, “be built up,” and “attaining to the whole measure of (lit. the height of) the fullness of Christ.”