Mat 24:21 For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.

Alternative: Because then there will be such great pressure as has not come into being from the beginner of the [current] world order until now, no, by no means shall [it] be produced.

The real point of this verse is that the "pressure" to bring an "end of an age" (or the end of a life) exists even when it is not produced. That pressure is inherent in the nature of things, arising from their existence not from our actions or lack of actions.

Civilizations fall and people die not because people's mistakes or intentional actions kill them but because their internal pressure drives them drives them naturally to a goal. These transitions may be difficult, but they are not due to "mistakes" (i.e. sins) or "burdens" (i.e. evil). These transitions are wrapped up in the purpose of existence.

It is unfortunate that this sense of the verse is lost completely in English translation, rendering this "pressure" as a "tribulation that shall be but never shall be." The more sensible meaning is hidden in a series of misleading translations, especially a extremely common mistranslation all through Matthew that renders the term "to become" or "to produce" as a version of the verb "to be." In the KJV of this verse, the first "shall be" (referring to "tribulation") is a form of the verb "to be," but the terms translated as "was" and "shall be" later in the verse are from the Greek word that means "to become" or "to be produced."

The word translated as "tribulation" means "pressure" and the same word that was earlier translated in a previous verse as "afflicted."

The world translated as "world" is not the same word translated previously in this chapter as "world." The word in this verse is kosmos, which Christ uses very specifically to mean the "world order." or "universal order."

"Tribulation" is from thlipsis, which means "pressure," "crushing," and "oppression." Earlier in Mat 24:9, it was defined as "afflicted."

"Beginning" is from archê, which means "beginning," "orgin," "first principles," "first place of power," "empire," and "command." This is the word from which we get both "archbishop," primal bishops who can consecrate other bishops, and "archeology," the study of ancient history.
"World" is from kosmos, which mean "order," "good order," "ruler," "world order," "universe," and "the world of men." Matthew uses it when Christ is talking about the order in the universe, specifically the world of men, as it is designed to be. It is NOT the word translated as "world" in Mat 24:3, which is aiôn or Mat 24:14, which is oikoumenê.

"Was" and the second, "shall be" are from gignomai (ginomai), which means "to become," "to come into being," "to be produced," and "to be." Only the first "shall be" is from a future form of "to be."