2 Thessalonians 1:8

in a flame of fire, executing judgment on all that know not God and obey not the gospel of our Lord Jesus;

2 Timothy 2:24

and the servant of the Lord must not contend, but must be gentle to all, apt to teach, patient under evil,

Hebrews 3:5-6

And Moses indeed was faithful in all his house, as a servant, for a testimony of things to be spoken;

1 Peter 2:8

and a stone of stumbling and rock of offense, who stumble at the word, being disobedient, to which also they were appointed.

1 Peter 4:17

For it is time for judgment to begin at the house of God; and if it first begins with us, what will the end be of those that 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, executing judgment on all that know not God and obey not the gospel of our Lord Jesus;
1 Peter 2:8
and a stone of stumbling and rock of offense, who stumble at the word, being disobedient, to which also they were appointed.
1 Peter 4:17
For it is time for judgment to begin at the house of God; and if it first begins with us, what will the end be of those that obey not the gospel of God?

Moses

2 Timothy 2:24
and the servant of the Lord must not contend, but must be gentle to all, apt to teach, patient under evil,
Hebrews 3:5
And Moses indeed was faithful in all his house, as a servant, for a testimony of things to be spoken;