I believe the first resurrection has already been instituted. When Jesus rose from the grave, He was fully and completely resurrected--the firstborn over Creation.The early church stood as the firstfruits of the resurrection.
It is Christ himself who is the firstfruits. Further, the end has not yet been attained:
But now is Christ risen from the dead, and become the firstfruits of them that slept. For since by man came death, by man came also the resurrection of the dead. For as in Adam all die, even so in Christ shall all be made alive. But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming. Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power. For he must reign, till he hath put all enemies under his feet. The last enemy that shall be destroyed is death. 1 Cr 15:20-26 KJV
When the day of reckoning comes,
The "day of reckoning" is a totally separate event from the resurrection/"rapture" issue. It is not the second coming. It is an event spoken of in the New Testament when the LORD returns and "reckoneth" with His servants (Matthew 18:24). The word is associated with an accounting, or a numbering, and the event is described in Matthew 25 with the parable of the 10 virgins (Matthew 25:19).
The Bible teaches about a time when GOD will sharply escalate his dealings with unrepentant mankind - and a time when He will reckon with His servants. Ironically, the specific period when God inaugurates the Reckoning is almost universally taught to be a time when He will do the exact opposite of what the scriptures actually tell us He will do.
In what may very well be the greatest tragedy of the last two centuries, the dispensational theorists have seized the reins of leadership in the "church" and as they have consolidated their power, they have widely programmed millions of church attendees into believing in something called the "rapture." The great irony of this is found in the fact that many of the verses put forth to describe the so-called "rapture" actually describe an event that may more appropriately be dubbed the Reckoning.
One of the most common errors seen in prophetic studies is our apparent propensity to consolidate many passages into the same event - especially when such a compression is unwarranted by the text. Thus, when we see a verse that describes the wrath of God, many simply say this is the same thing as the second coming.
Others, in seeking to "rightly divide the word of truth," arbitrarily assume the "wrath" spoken of in a tribulational context, is the second "half" of a theoretical seven-year tribulation. Because the doctrine of a seven-year great tribulation is itself false, the assignment of the passages dealing with the "wrath of God" into a portion of this faultily derived seven-year period then compounds the error.
Thus, error exponentially engenders further error until the prophetic chronology that is specified in scripture becomes so completely convoluted that retrieving basic truth becomes a Herculean task. The largest single offender in this babelistic bovine eskatology of the modern church is the false doctrine of dispensationalism - also known as the rapture cult.
Lest we offend the cultists with the erroneous assumption that in slashing the false doctrine of pretribulationism we're propagating preterism or some abstract and non-literal form of the second coming, I'll hasten to state that Jesus Christ IS coming back in our time. Furthermore, He IS coming back physically, just as the angels stated at His ascension, "this same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen him go into heaven."
The real question is not only WHEN is He coming back, but WHOM is He coming back to retrieve, and "what shall be the sign of His coming, and of the end of the world?"