We find in the end of Parshas Noach (Bereishis 11;31)

וַיִּקַּח תֶּרַח אֶת אַבְרָם בְּנוֹ וְאֶת לוֹט בֶּן הָרָן בֶּן בְּנוֹ וְאֵת שָׂרַי כַּלָּתוֹ אֵשֶׁת אַבְרָם בְּנוֹ וַיֵּצְאוּ אִתָּם מֵאוּר כַּשְׂדִּים לָלֶכֶת אַרְצָה כְּנַעַן וַיָּבֹאוּ עַד חָרָן וַיֵּשְׁבוּ שָׁם.

“And Terach took Avram his son and Lot the son of Haran, his grandson, and Sarai his daughter in law, the wife of Avram his son, and they went forth with them from Ur Kasdim to go to the land of Canaan, and they came as far as Charan and settled there.”

What inspired Terach to move from Ur to Canaan?

The Seforno suggests as follows:

לָלֶכֶת אַרְצָה כְּנַעַן. הַמּוּכֶנֶת אֶל גֶּרֶם הַמַּעֲלות בַּמֻּשְׂכָּלות, וּרְצוּיָה מִכָּל הָאֲרָצות, כְּאָמְרו “אֶרֶץ אֲשֶׁר ה’ אֱלהֶיךָ דּרֵשׁ אתָהּ” (דברים יא, יב). וְלא הֻזַּק אֲוִירָהּ בְּגֶשֶׁם הַמַּבּוּל כַּאֲוִיר כָּל שְׁאָר הָאֲרָצות, כְּאָמְרו “לא גֻּשְׁמָהּ בְּיום זָעַם” (יחזקאל כב, כד), וּכְבָר אָמְרוּ זִכְרונָם לִבְרָכָה ‘אֲוִירָהּ שֶׁל אֶרֶץ יִשְׂרָאֵל מַחְכִּים’.

We see that Canaan had special qualities that other lands did not have. In addition, the Chizkuni explains that Canaan was an inheritance from Shem, who was the ancestor of Terach so it made sense for him to go there.

We still need to understand why the journey ended prematurely?

Rabbi Shmuel Goldin in his work Unlocking the Torah Text suggests that perhaps Terach wanted to move away from his idolatry and chose to move out to Canaan which was known for its holiness. Along the way, perhaps he got sidetracked or the motivation waned. Rabbi Goldin suggests that this spark of Terach is what gave Avraham Avinu the burning motivation to complete his father’s journey to spirituality and eventually to move to Canaan.

 The Ohr Hachaim suggests that the reason for the move was because Terach was pained that Avraham and Sara still did not have children, so with the tradition of Shinui Makom Shinui Mazal, he picked up and moved, hoping that the change of residence would help Avram to have a grandchild.

The Malbim suggests similarly that since Avraham had no children he was not able to be as powerful, as power was given to those with large families.Therefore, Terach decided they should move out…

The Alshich explains that Terach was unable to make the full journey to Canaan because he was not going for the sake of going to Canaan. Rather, he went to escape the fires of Ur Kasdim, as he was not able to rely on a miracle to save him. Therefore, since his whole journey was just a means to escape, he had no problem settling in Charan, rather than Canaan.

The chain of events would make it seem that Avraham and his family were forced to move out of Ur Kasdim after he survived the incident with the furnace, It was at this point that Terach came under the influence of Avraham and knowing that Canaan was a holy ground he decided that that should be their next destination.

Rav Chaim Kanievsky explains based on the Sefer HaYashar that the journey from Ur Kasdim to Charan took 3 years. It is suggested that at this point of the journey, Terach was already frail and sickly and that is why the stayed in Charan. However, the distance from Charan to Canaan is not too far, so it seems surprising that after a three year journey, they would just give up right before the last leg of the trip.

We see later in Perek 16 Pasuk 7 that Hashem tells Avraham that He took him out of Ur Kasdim in order to bring him to Eretz Yisrael. this seems like it was a divinely inspired decision to stay in Charan so that Avraham can later have the full experience of the nisayon of Lech Lecha.

Benjamin of Tuleda writes of Charan as a very beautiful area;  and the Even Ezra suggests that that is why Terach decided to stay there.

We see that Terach held Avraham in high esteem and it could be that he really wanted to repent and come closer to Hashem, but due to various reasons never made it to his destination. We see this pattern throughout Jewish history, where many great men attempted to go up to Israel but were unable to complete the journey for various reasons.