naeil sueobe gyogwaseoreul gajigo gaseyo.

It comes from 가지다 + -고 + 가다.

• 가지다 = to have, hold, carry
• -고 = and, linking form
• 가다 = to go

But in this pattern, 가지고 가다 works as a single expression meaning to take something with you.

So it is not understood as two totally separate actions, like hold it and then go. Instead, it means go while carrying it / take it along.

In real speech, this is often shortened to:

• 갖고 가세요
• 가져가세요

All three are common, and in this sentence they mean basically the same thing.

에 marks the place, destination, or occasion connected with the action.

In 수업에 교과서를 가지고 가세요, 수업에 means something like:

• to class
• for class
• to your class session

So the sentence is telling someone to take the textbook along to the class tomorrow.

A native English speaker may expect something more like to class as a clear destination, and that is exactly what 에 is doing here.

를 is the object particle. It marks 교과서 as the thing being taken.

So:

• 교과서 = textbook
• 교과서를 = the textbook, as the object of the verb

You are taking what?
→ 교과서를

That is why 를 appears here.

Time words like 오늘, 내일, 어제 often appear without a particle in Korean.

So 내일 수업에 is completely natural and means:

• to class tomorrow
• for tomorrow’s class

You could add a particle in some situations, but it changes the feel:

• 내일은 adds contrast or emphasis, like as for tomorrow
• 내일에 is usually unnatural here

So the particle is omitted because that is the normal way to use this kind of time expression.

In this sentence, there is almost no meaning difference.

• 가지고 가세요 = take it with you
• 가져가세요 = take it with you

가져가세요 is a more contracted, very common form.
가지고 가세요 can feel a little more transparent to learners because you can clearly see the pieces.

You may also hear:

• 갖고 가세요

That is another common spoken contraction.

So these are all closely related and very natural.

This is about direction.

• 가다 = go
• 오다 = come

With objects:

• 가져가다 = take something away / take it there
• 가져오다 = bring something here

In 내일 수업에 교과서를 가지고 가세요, the idea is take the textbook with you to class.

A learner may wonder why Korean uses go here instead of come, since English often says bring your textbook to class. Korean chooses between go and come based on the speaker’s point of view more directly.

If the speaker sees the destination as there, 가다 is natural.
If the speaker sees it as here, 오다 may be used.

So English bring does not always match one single Korean verb.

-세요 makes the sentence a polite request or instruction.

So 가세요 here is not just plain go. It is more like:

• please take
• please bring
• make sure to take

It is polite and appropriate when speaking to:

• students
• customers
• someone you want to address respectfully

It is softer and more polite than a blunt command.

For example:

• 가지고 가세요 = polite
• 가지고 가 = casual, to a close friend or someone younger
• 가지고 가십시오 = more formal

It can feel a little broader than a direct one-word English match.

In this sentence, 수업에 most naturally means to class / for class. The point is that the textbook is needed in connection with that class.

Depending on context, 수업에 can sometimes be understood as:

• in class
• for class
• to class

But here, because the verb is 가지고 가세요 and the action is taking something somewhere, to class is the best way to understand it.

Yes, but the meaning becomes less specific.

• 책 = book
• 교과서 = textbook

So:

• 책을 가지고 가세요 = take the book with you
• 교과서를 가지고 가세요 = take the textbook with you

Using 교과서 tells the listener exactly what kind of book is meant. It is more precise and sounds more natural in a school/classroom context.

Yes, it is natural.

Very common everyday versions would be:

• 내일 수업에 교과서 가지고 가세요.
• 내일 수업에 교과서를 가져가세요.
• 내일 수업에 교과서 갖고 가세요.

In casual speech, Korean often drops particles when the meaning is still clear, especially the object particle 를. So 교과서를 may become 교과서 in conversation.

That said, the original sentence is clear, grammatical, and perfectly good for learners to study because it shows the structure neatly.