Tun und lassen in sentence

Question

I cannot understand the purpose of this phrase "tun und lassen", I saw it in sentence like this:

Das ist mein Auto. Ich kann damit tun und lassen, was ich will!

Translation in English (deepl.com):

This is my car. I can do what I want with it!

But if I change the sentence:

Das ist mein Auto. Ich kann damit tun, was ich will!

Translation in English (deepl.com):

This is my car. I can do what I want with it!

There is no change in the translation. I have tried other translators, same result.

In dict.cc it says that "Tun und Lassen" is idiom and it translates to "all sb.'s doings", but that makes no sense.

Is it used to emphasize something?

Answer 1

"Lassen" in this sentence is a bit like an antonyme to "tun". It means something along the lines of "to not do something", "to refrain from doing something" or "to let something happen (without doing something about it)".

To get a better idea, you might want to look at the related verb "zulassen". This is mostly translated along the lines of "to allow", "to permit". But "zulassen" has a more passive vibe than those. You can imagine it as something like "to tolerate something", "to not do anything to prevent something".

You could use "lassen" for example like this:

Ich könnte heute abend Joggen gehen. Oder ich könnte es lassen.

I could go running tonight. Or I could not.

or

Die Nachbarskinder machen wieder Krach im Garten! - Ach, lass' sie doch!

The neighbor's kids are making a ruckus again in the garden! - Oh, leave them be!

The set phrase

Ich kann tun und lassen, was ich will

is indeed a stronger emphasis compared to only "ich kann tun, was ich will". The speaker not only says that they can do whatever they want - it's also in their power to not do something, to refrain from something, or to not do anything at all.

There's also the variation "etwas sein lassen", which can be quite literally translated as "to leave something be".

Answer 2

The German tun und lassen is a fixed phrase (quite frequently used, see DWDS examples), emphasizing, that you not only have the choice, how you use something (my opinion: 2nd level choice), but even if you use it at all (1st level decision). My best translation is

I may do, whatever I want - even nothing if I feel like it.

Answer 3

The answer of Henning is already very good, I just want to dive a little bit deeper into the „lassen“ part.

The „tun und lassen“ phrase is usually used in combination with things that have a negative effect.

Lets take your example with the car:

The guy sais: I can do with it whatever I want (e.g. drive it against a wall).

But I can also choose to NOT do something that would be good for the car: I can can choose to not fill up missing oil... I can choose to not repair the brakes. I can choose to not wash the car at all.

Things that you normally would do, to make the car last longer / not break / look better: it‘s my car, and I can choose to not do them...

So I can choose what to do and what I wanna leave alone.