"Just how high did God fear they would build the tower?"
Artists inprepretation
The issue some has with the story of the Tower of Babel is more a misunderstanding of the text and the usage of the word 'heaven' then anything. God did not scatter them because they were able to build into God's heaven.
3 And they said one to another, Go to, let us make brick, and burn them thoroughly. And they had brick for stone, and slime had they for morter.
4 And they said, Go to, let us build us a city and a tower, whose top may reach unto heaven; and let us make us a name, lest we be scattered abroad upon the face of the whole earth.
5 And the LORD came down to see the city and the tower, which the children of men builded.
6 And the LORD said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do.
7 Go to, let us go down, and there confound their language, that they may not understand one another's speech.
8 So the LORD scattered them abroad from thence upon the face of all the earth: and they left off to build the city.
9 Therefore is the name of it called Babel; because the LORD did there confound the language of all the earth: and from thence did the LORD scatter them abroad upon the face of all the earth.
Heaven here is used as in meaning sky.
WHAT IS HEAVEN?
We often use the term Heaven loosely. The Bible actually refers to three heavens. The Bible uses the same word Heaven for three completely different places. And if you fail to make the distinction you can fall into doctrinal error.
We see the first Heaven in:
Gen 1:9 And God said, Let the waters under the heaven be gathered together unto one place, and let the dry [land] appear: and it was so.
Gen 1:20 And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl [that] may fly above the earth in the open firmament of heaven.
Jer 4:25 I beheld, and, lo, [there was] no man, and all the birds of the heavens were fled.
Dan 4:12 The leaves thereof [were] fair, and the fruit thereof much, and in it [was] meat for all: the beasts of the field had shadow under it, and the fowls of the heaven dwelt in the boughs thereof, and all flesh was fed of it.
From these verses we see the term Heaven used to describe our atmosphere. This is the heaven that we can see with our naked eyes.
The second Heaven is farther out than our atmosphere.
We see the second heaven in:
Gen 22:17 That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which [is] upon the sea shore; and thy seed shall possess the gate of his enemies;
Neh 9:23 Their children also multipliedst thou as the stars of heaven, and broughtest them into the land, concerning which thou hadst promised to their fathers, that they should go in to possess [it].
From these verses we see heaven is used to describe the stellar heavens.
This is the heaven that we can see with telescopes. But even with the most advance telescopes we can only see a tiny fraction of the stellar heavens.
We see the third heaven in:
1Ki 8:27 But will God indeed dwell on the earth? behold, the heaven and heaven of heavens cannot contain thee; how much less this house that I have builded?
1Ki 8:30 And hearken thou to the supplication of thy servant, and of thy people Israel, when they shall pray toward this place: and hear thou in heaven thy dwelling place: and when thou hearest, forgive.
1Ki 8:39 Then hear thou in heaven thy dwelling place, and forgive, and do, and give to every man according to his ways, whose heart thou knowest; (for thou, [even] thou only, knowest the hearts of all the children of men
wink From these verses we see the term heaven used to describe the Abode of God.
This is the heaven that we see thru the eyes of faith.
It was the third heaven, it was the abode of God that Paul got caught up to.
2Co 12:2 I knew a man in Christ above fourteen years ago, (whether in the body, I cannot tell; or whether out of the body, I cannot tell: God knoweth
wink such an one caught up to the third heaven.
The word heaven is used in the Bible to describe three completely different places. The atmosphere, the stellar heavens, and the abode of God. When you see the word heaven in the Bible, you need to look at the context to tell which one is being referred to.
So basically they built a very tall tower to make themselves a name, that they would not be scatted around the world. Very prideful wouldn't you say?