We ask the following database query: What are the common and different characteristics of the 10 plagues that God brought on Egypt. The reader is encouraged to perform the query using a standard Biblical Konnkordance or search engine. This database query yields the list below. The list justifies the following Rashi inference: The 10 plagues naturally organize into 3 groups: (a) Plagues 1,4,7 are attacks on Egyptian gods and a cut off of land and sea access.(b) Plagues 2,5,8 humiliated the Egyptians and took away their pride. (c) Plagues 3,6,9 caused the people pain. (d)The 10th plague culminated all and freed the Jews. This follows a military sequence of a) cut off of supplies b) causing confusion and fear and c) inflicting pain to induce surrender. The list below presents the results of the database query.

#	Plague	Verse	Intro phrase	Military tactic
1	Blood	Ex07-15	At morn approach Pharoh on Nile	Sea/air/deity cut off
4	Beasts	Ex08-16	At morn approach Pharoh on Nile	Sea/Air/deity cut off
7	Hail	Ex09-13	At morn approach Pharoh on Nile	Sea/Air/deity cut off
-	----	------	------	-----
2	Frogs	Ex07-26	Come to Pharoh	Humiliation
5	Plagues	Ex09-01	Come to Pharoh	Humiliation
8	Locust	Ex10-01	Come to Pharoh	Humiliation
-	----	------	------	-----
3	Lice	Ex08-12	No intro phrase	Unwarned pain
6	Boils	Ex09-08	No intro phrase	Unwarned pain
9	Darkness	Ex11-21	No intro phrase	Unwarned pain

Advanced Rashi: Just to recap:
• When waging war you 1st cut off spiritual, land and water access. The intro phrase In the morn Go to Pharoh on the Nile is basically a statement that the Egyptian water and god (Nile) would be cut off
• After cutting off supplies you demoralize the enemy and rob them of their pride by humiliating them. The lack of pride facilitates surrender. Hence the introductory phrase Go visit Pharoh to emphasize an invasion of his personal air space.
• Finally if the above doesn't work you inflict pain on the enemy to induce them to surrender. Consequently there is no introductory phrase to plagues 3,6,9 since the point is that you don't want to warn them and don't want them to prepare.
• As indicated above, the 3rd, 6th and ninth plague involved infliction of pain. Hence there is no introductory passage And God said to Moses Come to Pharoh... The lack of such a communication intensifies the pain. By contrast the purpose of the other plagues was to cut off land-sea supplies and to humiliate the Egyptians - hence a verbal warning accompanied them. Consequently plagues 1,2,4,5,7,8 being with an introductory God said to Moses Go to Pharoh and tell him... In this case the communication intensifies the intended humiliation.

The above analysis was started by Rashi and complemented by Rabbi Hirsch. Much more could be said but the above table paves the way for further analysis.