The biblical phrase “The Day of the Lord” (or, ‘That Day’) encapsulates everything to do with the 7-year-long Great Tribulation (a.k.a. Jacob’s Trouble), including the culmination of the Tribulation period — the Second Advent of Christ. Sometimes, Old Testament prophets will refer to “the Day of the Lord” while talking about the events at its beginning, throughout the period or at its ending… or all of these. In fact, every indication tells us that similar celestial signs will mark its beginning and end (Joel 2:30-31; Matthew 24:29; Mark 13; Luke 21).
In deciphering the prophets, one must recognize what part of the Day of the Lord is being described, or if the author may be describing an event associated with the Day of the Lord that can have several iterations of fulfillment. For example, the combinations of solar eclipse followed by lunar eclipse, occurring on certain Torah Feast Days, have several iterations. If one does not differentiate between passages like Joel 2:30-31 and Matthew 24:29, then the Apostle Peter seems to contradict Jesus by quoting Joel in his Pentecost Sermon, as recorded in Acts 2. But, Peter and Jesus are not in contradiction; because on the day Jesus died, there was a total solar eclipse. Not long after that, there was a blood moon (See Good Friday: The Day the Moon Turned to Blood by Bob Hayton). Moreover, when Jesus spoke Matthew 24:29-30, he was describing the end of the Great Tribulation.
At this point in the discussion of the Day of the Lord, it is extremely important to note that the events of Jesus’ death & resurrection, along with Pentecost, are themselves part of “the Day of the Lord.” Just as the event of Christ’s return will be the culmination of the Day of the Lord, even so the events of Christ’s first Advent (including Pentecost) are inceptions of The Day of the Lord. Again, Peter attests to this fact in Acts 2.
Whenever solar eclipses are answered by blood moons on God’s appointed days, one can be sure something significant is happening in regards to the Day of the Lord. Joel tells us so. That being said, there WAS a rare solar eclipse this past March 20, 2015, followed by a blood moon on April 4. What is more, there will be a partial solar eclipse on Sept. 13, 2015 followed by a total lunar eclipse on Sept. 28, 2015 (see Dates of Next Lunar and Solar Eclipses by EarthSky.org). These dates coincide with Jewish New Year (Rosh Hosanna/Yom Teru’ah) and Sukkot. Also, the Day of Atonement (23rd) is sandwiched between them. Could this double iteration of “sun will be turned to darkness and the moon into blood” on the appointed days not be an accurate fulfillment of the reading of Joel 2:30-31? I believe it is indeed a fulfillment.
Worthy scholars have attacked Blood Moon prophets like Mark Biltz, even labeling him a false prophet. These accusations are built on what I believe to be “straw man” arguments that Mr. Biltz sets dates for the Second Advent. To be sure, Mr. Biltz has said that Feast Days and according Blood Moons are connected to the Return of Messiah, as well as many other prophetic events on God’s appointed days, awaiting fulfillment. In Biltz’s understanding, when Christ returns, He will return on “A” Feast of Trumpets. That is different than saying, Christ will return on “this” (2015) Feast of Trumpets. Also, Mr. Biltz has directly said he is not date setting. For a direct quote from Mark Biltz on the matter, please see this video, proceeding from 0:00 to 4:47. When Mr. Biltz does say things like, “The Lord is coming soon,” I take him to mean the same concept any premillennial theologian communicates—the Second Advent is soon but not as imminent as the rapture and/or Tribulation, but that, there are signs of the nearness of Messiah’s Second Coming (Matthew 24). If Mark Biltz is stating anything concretely predictive, I understand him to be implying that this Feast of Trumpets (2015) will bring the Rapture of the Church and/or the beginning of the Great Tribulation — The Battle of Gog and Magog (Ezekiel 38, Psalm 83). A similar view is also held by Bill Salus.
Lastly, scholars charge Mark Biltz as a false prophet by pointing out that the sun must be darkened and the moon turned to blood at the same time, if Joel 2:30-31 is accurately fulfilled. However, the Joel passage does not indicate simultaneous darkening of the sun and reddening of the moon. Rather, in Peter’s eyes, the clear connection (of hours or days) of the two eclipses was an accurate fulfillment of Joel 2:30-31.
[Last Update: Sept. 7, 2015, 5:00pm EST]
BibleHub – Isaiah 13:9 parallel and cross reference study
BibleHub – 1 Thess. 5:2 parallel and cross reference study
The Day of the Lord by John Walvoord
Day of the Lord, the (BEDBT) via Bible Study Tools
Day of the Lord key search term on BibleGateway
What is the Day of the Lord? by GotQuestions
Harbinger Search results, key word “Day of the Lord”