I'll answer these in order. It is/was not necessary to mention it, for "repenting" is part and parcel of "believing". (Note there is a slight difference in the 'force' of a verb form and a noun form which we be expanded on momentarily.)
The lack of mention of "repenting", in the Acts passage does necessarily "mean you don't even have to repent", at all. But the question is unclear, as asked, thus far. The key question is the next one you asked Quote:
And what does repent even mean?
Here is what "repent" means in the NT. There are two words rendered "repent" in the NT, at least in the KJV. The one that is far more common is "metanoeO" (I use the upper case "O" to transliterate 'omega', and the lower case for 'omicron', to differentiate.), and is used some 30 times. This word means
to think afterward (
or differently), and in fact contains within itself the root word ("nous") for 'mind' hence
is associated with the intellect, and is the word the NT uses in every instance as having anything to do with salvation. The second word rendered "repent" is "metamellomai", and is used 6 times. This word means
to care (
or feel)
afterward (
or differently), and contains the middle voice of the root word ("melo") hence, a reflexive use for 'concern' or 'to concern oneself', and is
associated with the emotions. The word rendered "repentance" in the NT in every case, is the word "metanoia" the noun form of "metanoeO', and thus, refers to "a change of mind".
The OT word is apparently "nacham" (And here I am relying on several others, not understanding neither any Hebrew nor Chaldee.), and appartently carries the force of "to be eased", or of 'reflexive compassion' and is probably closer to 'metamellomai', than to 'metanoeO', although there could be some slight 'blurring' here, IMO. (There are three instances where the KJV renders "shub" as repent, but it would undoubtedly be better rendered as 'turn' or 'return' or something akin, as it is in some 600 other places in the OT, and in fact, the ASV, RV and NKJV all render it in this manner.) The one OT quote in the NT that has "repent" in some form is rendered with 'metamellomai' in Hebrews 7:21.
We often get into trouble, IMO, by attempting to read later English, especially 'church speak' back into Scripture. I've heard more sermons than I can count on my 10 fingers where one has spoken about David 'repenting' after his episode with Bathsheba.
Only one problem with this. The Bible never says this, anywhere, as far as I can tell. Did David 'acknowledge' his sin? Absolutely! Did David 'confess' his sin? Again, the answer is definitely yes. Did David "repent of his sin"? Scripture doesn't say this. In fact, only one
individual human in the OT is ever said, in any manner, to repent, and that is Job. (Job 42:6) (And he didn't have to get "cleaned up" to do it, either, for he was already covered "in sackcloth and ashes".) But you might consider that God is said to 'repent' and/or not 'repent' over 30 times. And I assure you,
I'm not about to suggest that God was in any way involved with sin.
And the Bible never uses the phrase "
repent of (or for) one(s) sins"
in any manner whatsoever, let alone, making some supposed distinction between the ones which "are fresh on one's mind' and the ones "which have been forgotten". And I am very leery of (mis)using the Bible in this manner, personally. I'd personally suggest directing repentance in the two ways found in Scripture, "(Edited, here to remove a misprint)
...repentance toward God, and faith toward our Lord Jesus Christ." (Acts 20:21) and "
...repentance from dead works and faith toward God,"...(Heb. 6:1), and associating it with the related idea of 'faith' found in the same two passages.
Hope this is a bit informative. (
http://www.baptistboard.com/showthread.php?t=35228&page=3 post #23 You might also check out post # 37 in the same thread.)