At one time the Buddha was staying in the land of the Vajjis at the village of Koṭi.

There the Buddha addressed the mendicants: “Mendicants, due to not understanding and not penetrating four noble truths, both you and I have wandered and transmigrated for such a very long time.

What four? The noble truths of suffering, the origin of suffering, the cessation of suffering, and the practice that leads to the cessation of suffering. 

These noble truths of suffering, origin, cessation, and the path have been understood and comprehended.

Craving for continued existence has been cut off; the conduit to rebirth is ended; now there’ll be no more future lives.”

That is what the Buddha said. Then the Holy One, the Teacher, went on to say:

“Because of not truly seeing
the four noble truths,
we have transmigrated for a long time
from one rebirth to the next.
But now that these truths have been seen,
the conduit to rebirth is eradicated.
The root of suffering is cut off,
now there’ll be no more future lives.”

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The Buddha is sharing a teaching on the impact of not understanding the four noble truths - one continues to experience rebirth, and on the impact of understanding the four noble truths - one ends the cycle of rebirth through wisdom.

The Buddha often advised his students to recognise any time they find themselves engaged in thinking unskilfully, pondering over metaphysics, when they’re arguing, when they are engaging in low talk, to instead come back to reflect and verify the four noble truths, and to meditate.

They’re described here in brief. Further readings on them are:
* https://www.reddit.com/r/WordsOfTheBuddha/comments/18ium7w/teachings_on_living_beings_and_the_five_aggregates/
* https://www.reddit.com/r/WordsOfTheBuddha/comments/18p8m3i/the_characteristic_of_notself_sn_2259/

The four noble truths cuts off future lives (SN 56.22)