Friends:

What are the Benefits of Training Mental Concentration?

Once in Savatthi the Blessed Buddha said this:
Bhikkhus, train and develop concentration! Any Bhikkhu, who is concentrated
understands things as they really are and as they really become! How?
1: He understands as it really is: This and such is Suffering,
2: He understands as it really is: This and such is the Cause of Suffering,
3: He understands as it really is: This and such is the Ceasing of Suffering,
4: He understands as it really is: This is the Way leading to the End of Suffering!
Bhikkhus, develop concentration! A Bhikkhu, who is concentrated understands
not only the appearance, but things as they really are and as they really become!
Therefore, Bhikkhus, an effort should be made to comprehensively understand:
This is Suffering; This is the Cause of Suffering; This is the End of Suffering;
This is the way leading to the End of Suffering... An effort should be made to
comprehend, fathom, grasp, understand, and penetrate these Four Noble Truths!

                          

Comments:
Those who makes that effort, and understands, shortens this Samsaric round...
Those who neglects that effort, and ignores it, prolongs this Samsaric round...

 

More on these 4 Noble truths:
http://What-Buddha-Said.net/drops/II/The_4_Noble_Truths.htm
http://What-Buddha-Said.net/drops/II/The_1st_Noble_Truth_on_Suffering.htm
http://What-Buddha-Said.net/drops/II/The_2nd_Noble_Truth_on_The_Cause_of_Suffering.htm
http://What-Buddha-Said.net/drops/II/The_3rd_Noble_Truth_on_The_Ceasing_of_Suffering.htm
http://What-Buddha-Said.net/drops/II/The_4th_Noble_Truth_on_The_Way_to_End_Suffering.htm

Source (edited extract):
The Grouped Sayings of the Buddha. Samyutta Nikāya. [V:414]
section 56: Saccasamyutta. Thread 1: Concentration...

Terse Truths!