Isaiah 33:19

Thou shalt not see a firm people, a people of a deep lip above,hearing; of a stammering tongue, of no understanding.

Isaiah 28:11

For with the stammerings of the lip and with another tongue he will speak to this people.

Deuteronomy 28:49-50

Jehovah shall raise up against thee a nation from far off, from the extremity of the earth, as the eagle shall fly, whose tongue thou shalt not hear;

Jeremiah 5:15

Behold me bringing upon you a nation from far off, O house of Israel, says Jehovah: it is a nation of strength, it is a nation of old, a nation thou wilt not know its tongue, and thou shalt not hear what it will speak.

2 Kings 19:32

Therefore, thus said Jehovah to the king of Assur, He shall not come into this city, and he shall not shoot an arrow there, and a shield shall not come before it, and he shall not cast a mound against it

Ezekiel 3:5-6

For not to a people deep of lip and heavy of tongue; thou art sent to the house of Israel;

Exodus 14:13

And Moses will say to the people, Ye shall not fear; stand ye and see the deliverance of Jehovah, which he will do to you this day: for the Egyptians whom ye saw this day, ye shall not add to see them more forever.

1 Corinthians 14:21

It has been written in the law, That in other tongues and in other lips will I speak to this people; and not so will they hear me, says the Lord.

Treasury of Scripture Knowledge

Summary

Thou shalt not see a fierce people, a people of a deeper speech than thou canst perceive; of a stammering tongue, that thou canst not understand.

Bible References

Shalt not

Exodus 14:13
And Moses will say to the people, Ye shall not fear; stand ye and see the deliverance of Jehovah, which he will do to you this day: for the Egyptians whom ye saw this day, ye shall not add to see them more forever.
Deuteronomy 28:49
Jehovah shall raise up against thee a nation from far off, from the extremity of the earth, as the eagle shall fly, whose tongue thou shalt not hear;
2 Kings 19:32
Therefore, thus said Jehovah to the king of Assur, He shall not come into this city, and he shall not shoot an arrow there, and a shield shall not come before it, and he shall not cast a mound against it

Deeper

Isaiah 28:11
For with the stammerings of the lip and with another tongue he will speak to this people.
Jeremiah 5:15
Behold me bringing upon you a nation from far off, O house of Israel, says Jehovah: it is a nation of strength, it is a nation of old, a nation thou wilt not know its tongue, and thou shalt not hear what it will speak.
Ezekiel 3:5
For not to a people deep of lip and heavy of tongue; thou art sent to the house of Israel;
1 Corinthians 14:21
It has been written in the law, That in other tongues and in other lips will I speak to this people; and not so will they hear me, says the Lord.