...I am the Lord, and I will
bring you out from under the burdens of the Egyptians, and I will
deliver you from their bondage, and I will redeem you with an
outstretched arm, and with great judgments; and I will take you to Me
for a people, and I will be to you a God; and ye shall know that I am
the Lord your God, who brought you out from under the burdens of the
Egyptians. And I will bring you in unto the land, concerning which I
lifted up My hand to give it to Abraham, to Isaac, and to Jacob; and I
will give it you for a heritage: I am the Lord. (Exodus 6:6-8, JPS)
God makes it very clear to the children of Israel that the objective of the exodus is the subsequent arrival in the land of Israel. The exodus from Egypt is not merely a liberation from slavery, but a means of attaining the land of Israel and the fulfillment of historical destiny. The most tragic and severely punished event in the entire Torah, found in Numbers 13, is when Moses' spies return from exploring the land of Israel and say that they prefer Egypt. Throughout the Tanakh, Egypt and Israel are set up as two opposing and mutually exclusive ideological/cultural paradigms.
If we adhere to God's word, we will be protected from the afflictions that God placed on Egypt:
and said, "If thou wilt diligently hearken to the voice of the LORD
thy God, and wilt do that which is right in His sight, and wilt give
ear to His commandments and keep all His statutes, I will put none of
these diseases upon thee which I have brought upon the Egyptians; for
I am the LORD that healeth thee." (Exodus 15:26, KJV)
And by the same token, all the afflictions that God placed on Egypt are given as a punishment for disobedience:
Moreover He will bring upon thee all the diseases of Egypt which thou
wast afraid of, and they shall cleave unto thee. (Deut. 28:60, KJV)
The return to Egypt described in Deuteronomy 28:68, “a journey which I promised you should never make,” describes the exile from the land of Israel as an undermining and reversal of the entire exodus process.
This prophecy was fulfilled when the Babylonian empire exiled the people of Israel and destroyed the First Temple. It's a matter of tragic irony that this prophecy of doom would not be directly fulfilled by the Babylonians, but by the frieghtened people of Israel who leave on their own accord:
"Thus saith the LORD, the God of Israel, unto whom ye sent
me to present your supplication before Him: 'If ye will still abide
in this land [the land of Israel], then will I build you and not pull you down, and I will
plant you and not pluck you up; for I repent of the evil that I have
done unto you. Be not afraid of the king of Babylon, of whom ye are
afraid; be not afraid of him, saith the LORD, for I am with you to
save you and to deliver you from his hand. And I will show mercies
unto you, that he may have mercy upon you and cause you to return to
your own land.' "But if ye say, 'We will not dwell in this land,'
neither obey the voice of the LORD your God, saying, 'No, but we
will go into the land of Egypt where we shall see no war, nor hear the
sound of the trumpet, nor have hunger for bread, and there will we
dwell'-- and now therefore hear the word of the LORD, ye remnant of
Judah! Thus saith the LORD of hosts, the God of Israel: 'If ye wholly
set your faces to enter into Egypt, and go to sojourn there, then
it shall come to pass that the sword which ye feared shall overtake
you there in the land of Egypt, and the famine whereof ye were afraid
shall follow close after you there in Egypt; and there ye shall die.
So shall it be with all the men that set their faces to go into
Egypt to sojourn there. They shall die by the sword, by the famine,
and by the pestilence; and none of them shall remain or escape from
the evil that I will bring upon them.'
(Jeremiah 42:9-17, KJV)
...then spoke
Azariah the son of Hoshaiah, and Johanan the son of Kareah, and all
the proud men, saying unto Jeremiah, "Thou speakest falsely. The LORD
our God hath not sent thee to say, 'Go not into Egypt to sojourn
there.' But Baruch the son of Neriah setteth thee against us, to
deliver us into the hand of the Chaldeans, that they might put us to
death and carry us away captives into Babylon." So Johanan the son of
Kareah, and all the captains of the forces, and all the people obeyed
not the voice of the LORD to dwell in the land of Judah. But Johanan
the son of Kareah and all the captains of the forces took all the
remnant of Judah, who had returned from all nations whither they had
been driven, to dwell in the land of Judah-- even men, and women, and
children, and the king's daughters, and every person whom Nebuzaradan
the captain of the guard had left with Gedaliah the son of Ahikam, the
son of Shaphan, and Jeremiah the prophet, and Baruch the son of
Neriah. So they came into the land of Egypt, for they obeyed not the
voice of the LORD; thus came they even to Tahpanhes.
(Jeremiah 43:2-7 KJV)
It's worth reading Jeremiah 42 and 43 in full since these are awesome chapters.