2 Thessalonians 1:8

in a flame of fire, taking vengeance of them that know not God, and obey not the gospel of our Lord Jesus Christ:

2 Timothy 2:24

And a servant of the Lord ought not to quarrel; but to be gentle to all men, apt to teach, forbearing,

Hebrews 3:5-6

And Moses indeed was faithful in all that house of his as a servant, to bear testimony of the things which should be after spoken;

1 Peter 2:8

and a stone of stumbling, and rock of offence," to those who stumble at the word, disobedient; whereunto also they were appointed.

1 Peter 4:17

For now is the time when judgment is commencing at the house of God; and if it begin with us, what will be the end of those who obey not the gospel of God?

Treasury of Scripture Knowledge

Summary

Because they obeyed not the voice of the LORD their God, but transgressed his covenant, and all that Moses the servant of the LORD commanded, and would not hear them, nor do them.

Bible References

They obeyed not

2 Thessalonians 1:8
in a flame of fire, taking vengeance of them that know not God, and obey not the gospel of our Lord Jesus Christ:
1 Peter 2:8
and a stone of stumbling, and rock of offence," to those who stumble at the word, disobedient; whereunto also they were appointed.
1 Peter 4:17
For now is the time when judgment is commencing at the house of God; and if it begin with us, what will be the end of those who obey not the gospel of God?

Moses

2 Timothy 2:24
And a servant of the Lord ought not to quarrel; but to be gentle to all men, apt to teach, forbearing,
Hebrews 3:5
And Moses indeed was faithful in all that house of his as a servant, to bear testimony of the things which should be after spoken;