The first is active voice, the second is passive voice.
You might use passive voice when you don't know who did something (I was mugged) or if you don't want to say (Your vase got broken), or it's not important to say (The surveys were carried out over a three year period).
In all other circumstances, active voice is better: it's more concise, easier to understand and, most importantly, says who is doing something.
The expression coming out of your mouth is fine if what was said is inappropriate or offensive. If what's said is quite proper but not expected from this particular person, from your lips might be better.
So, you could say any of these:
I didn’t expect such things coming out of your mouth.
I didn't expect such things from your lips.
Generally, you take revenge on someone, or for something - you don't take it from them. There are multiple ways of expressing this:
to take revenge (against somebody)
to seek revenge (against someone)
get revenge against someone
take revenge (on someone) (for something)
However, in the example you have provided:
One day my son will grow up and get my revenge from you.
...implies that the son is taking the father's revenge, which is not possible. Revenge is a personal thing - you can take it for yourself, or you can take it on behalf of somebody else, but you can't take somebody else's revenge. The closest alternatives to your sentence would probably be along the lines of:
One day my son will grow up and take/seek/get his revenge (from you).
One day my sone will grow up and revenge me. (correct, but not commonly used)
Another alternative available is the word avenge, which (in my opinion) is more suited to this scenario.
avenge and revenge both mean to seek or get vengeance. However, avenge specifically means to take vengeance or exact satisfaction for (a wrong) by punishing the wrongdoer, which is exactly what you describe.
...are two ways of expressing this, but it can be reworded in a number of fashions.
Best Answer
"You may get shocked" is a perfectly natural way to express this. Your second variant:
Would be more natural if you used "electric" in place of "electrical." Here are the dictionary definitions for those two words (from Oxford Dictionaries):