2 Chronicles 7:22

and they have said, Because that they have forsaken Jehovah, God of their fathers, who brought them out from the land of Egypt, and lay hold on other gods, and bow themselves to them, and serve them, therefore He hath brought upon them all this evil.'

Judges 2:12-13

and forsake Jehovah, God of their fathers, who bringeth them out from the land of Egypt, and go after other gods (of the gods of the peoples who are round about them), and bow themselves to them, and provoke Jehovah,

2 Chronicles 36:17

And He causeth to go up against them the king of the Chaldeans, and he slayeth their chosen ones by the sword in the house of their sanctuary, and hath had no pity on young man and virgin, old man and very aged -- the whole He hath given into his hand.

Jeremiah 1:16

And I have spoken My judgments with them concerning all their evil, in that they have forsaken Me, and make perfume to other gods, and bow themselves to the works of their own hands.

Lamentations 2:16-17

Opened against thee their mouth have all thine enemies, They have hissed, yea, they gnash the teeth, They have said: 'We have swallowed her up, Surely this is the day that we looked for, We have found -- we have seen.'

Lamentations 4:13-15

Because of the sins of her prophets, The iniquities of her priests, Who are shedding in her midst the blood of the righteous,

Ezekiel 14:23

And they have comforted you, for ye see their way and their doings, and ye have known that not for nought have I done all that which I have done in her -- an affirmation of the Lord Jehovah.'

Ezekiel 36:17-20

'Son of man, The house of Israel are dwelling on their land, And they defile it by their way and by their doings, As the uncleanness of a separated one hath their way been before Me.

Daniel 9:12

'And He confirmeth His words that He hath spoken against us, and against our judges who have judged us, to bring in upon us great evil, in that it hath not been done under the whole heavens as it hath been done in Jerusalem,

Treasury of Scripture Knowledge

Summary

And it shall be answered, Because they forsook the LORD God of their fathers, which brought them forth out of the land of Egypt, and laid hold on other gods, and worshipped them, and served them: therefore hath he brought all this evil upon them.

Bible References

Because they forsook

Judges 2:12
and forsake Jehovah, God of their fathers, who bringeth them out from the land of Egypt, and go after other gods (of the gods of the peoples who are round about them), and bow themselves to them, and provoke Jehovah,
Jeremiah 1:16
And I have spoken My judgments with them concerning all their evil, in that they have forsaken Me, and make perfume to other gods, and bow themselves to the works of their own hands.
Lamentations 2:16
Opened against thee their mouth have all thine enemies, They have hissed, yea, they gnash the teeth, They have said: 'We have swallowed her up, Surely this is the day that we looked for, We have found -- we have seen.'
Lamentations 4:13
Because of the sins of her prophets, The iniquities of her priests, Who are shedding in her midst the blood of the righteous,
Ezekiel 14:23
And they have comforted you, for ye see their way and their doings, and ye have known that not for nought have I done all that which I have done in her -- an affirmation of the Lord Jehovah.'
Ezekiel 36:17
'Son of man, The house of Israel are dwelling on their land, And they defile it by their way and by their doings, As the uncleanness of a separated one hath their way been before Me.

Therefore

2 Chronicles 36:17
And He causeth to go up against them the king of the Chaldeans, and he slayeth their chosen ones by the sword in the house of their sanctuary, and hath had no pity on young man and virgin, old man and very aged -- the whole He hath given into his hand.
Daniel 9:12
'And He confirmeth His words that He hath spoken against us, and against our judges who have judged us, to bring in upon us great evil, in that it hath not been done under the whole heavens as it hath been done in Jerusalem,

General references

Deuteronomy 29:24
yea, all the nations have said, Wherefore hath Jehovah done thus to this land? what the heat of this great anger?
Jeremiah 22:8
And many nations have passed by this city, And they have said, each to his neighbour, For what hath Jehovah done thus to this great city?
Ezekiel 20:48
And seen have all flesh, that I, Jehovah, have kindled it -- it is not quenched.'