In Acts 2:17-21 Peter is quoting the prophet Joel about the last days. So, did the last days start during Peters time? Or was it later? How can we know we are not simply excited about big changes in society and calling it the end times? There were big changes going on during Peters time as well and yet he died without seeing the return of Christ. Might we simply be doing the same thing and are also destined to die without seeing Christs return?
The phrase “last days” is used 5 times in the New Testament and covers everything from the entire Church Age (2X) to the Great Tribulation. (3X) In Acts 2:17-21 Peter used the term in its broadest sense.
Also, when Peter referred to the last days in Acts 2, the Lord hadn’t yet disclosed that Israel was being set aside for a period of time while He focused on the Gentile Church, and after that He would turn His attention to Israel again. This was first revealed in Acts 15:13-18, using a quote from Amos 9:11-12. Since then the world has been waiting for Israel to re-appear as the first major sign that the last days really are upon us. This finally happened in 1948. Jesus said that many of the people being born when the first signs appeared would still be alive when He comes back. (Matt. 24:34)