Tanakh Lab reveals that one of the most significant roots in the the chapter is "חזק". Using the concordance to trace the usage of both the adjective and verbal root in Torah demonstrates that it repeats throughout the Exodus narrative, referring on one hand to Paroh's obstinance in preventing the Exodus and on the other to God's mighty hand which brings it about, emphasizing the reversal and salvation that have taken place in the story.1
Articles – See R. Nathaniel Helfgot שתי מילים מנחות בסיפור יציאת מצרים, who explores the usages of the two roots כבד and חזק, noting how the repetition of the roots demonstrates Hashem's measure for measure actions during the Exodus.2
Symbolism
Fire
Fire – Using the concordance demonstrates that fire is often a vehicle of Hashem’s revelation, becoming a symbol thereof as well. Fire has appeared in the context of the Covenant Between the Pieces, the destruction of Sedom, the plagues, and the pillar of cloud and fire that led the Israelites in the desert. Fire appears many times subsequently in the Torah, as well, often in the context of divine wrath and destruction.
Articles – Several articles touch on the symbol:
See The Eternal Flame, by R. David Silverberg, for an analysis of consuming fire as a symbol of divine punishment and non-destructive fire as a symbol of Hashem’s presence. See קול אלקים מדבר מתוך האש, by R. Amnon Bazak, for analysis of how Torah’s descriptions of the fire of Sinai in Shemot and Devarim are meant to impart three fundamental religious beliefs: God’s incorporeality, the prohibition of idolatry, and the truth of Moshe’s prophecy.
Cloud
Cloud – Using the concordance demonstrates that clouds (like fire) are often a vehicle of Hashem’s revelation, becoming a symbol thereof as well.
Articles –
See Pillar of Fire, Pillar of Cloud, by R. Tamir Granot, for analysis of the phenomenon of Hashem’s revelation through natural phenomena such as fire and clouds. He suggests that in Tanakh, the cloud and pillar of fire are not two distinct modes of revelation, but one and the same. God's glory is manifest as fire which is screened by the cloud. It is referred to as one or the other due to the perception of the viewer, who might see fire at night, but only cloud during the day.
See For the Cloud Rested Upon It, by R. Shimon Klein, for exploration of the distinct symbols of fire and cloud. He suggests that fire represents Hashem’s actions and manifestation while the cloud represents man’s encounter with Him.