What holds the Universe together?   
What causes Nature to run its course in an orderly fashion.   
What enables a person to Exist and to experience Love, Joy and Peace?   

Christ Jesus (the Word of God) is "upholding all things by the word of his power".   Heb 1:3

God designed the Universe to exist and operate in Order by, on and through the Word Of His Power.   
This is the force that cosmologists and physicists will never find by searching the Physical Universe.   
It is revealed in the Bible by the Holy Spirit.   

Since man was given Dominion over the Earth by God, man determines the extent to which the Word Of His Power is effective.   
As the spirit of Anti Christ is stealing the minds and hearts of people, the Word Of His Power is `weakened` in the hearts of the Deceived.   
As Christians fail to exercise the Word the Word Of His Power is not unleashed in their lives or in Nature.   

When the great Tribulation occurs it will be because the Word Of His Power has been so weakened that nature convulses into chaos manifesting earthquakes and floods, Physical ailments arise and spread swiftly that baffle Medical Science.   

Because of these troubles absolute Political power will be given to the Beast ( Anti Christ) to fix all that is wrong in the Earth.   His methods will be harsh and totally ineffective.   

When Christ Jesus Returns He will re-institute Order by the Word of His mouth.   

Repent; or else I will come unto you quickly, and will fight against them with the sword of my mouth. Rev 2:16 He is called to repent by cleaning us the licenciousness and heresy.     The Word Of The Lord contains both blessing and cursing.     Their acceptance of sin would eventually leat to them experiencing the curse.

And out of his mouth goes a sharp sword, that with it he should strike the nations: and he shall rule them with a rod of iron: and he treads the winepress of the fierceness and wrath of Almighty the Lord. Rev 19:15 Our Lord Jesus is the instrument of the Lord's wrath, His judgment and His salvation.

And the remnant were slain with the sword of him that sat upon the horse, which sword proceeded out of his mouth: and all the fowls were filled with their flesh. Rev 19:21 Everyone who fights against the Christ when He returns will be slain by the Word Of His Power.

The " Word of His mouth" is the Word Of His Power issuing from His mouth.