EZEKIEL 2:4
[NKJV]
For they are impudent and stubborn children. I am sending you to them, and you shall say to them, ‘Thus says the Lord God.’
[BSB]
They are obstinate and stubborn children. I am sending you to them, and you are to say to them, ‘This is what the Lord GOD says.’
Though the Lord God sent different Messengers to stubborn people to deliver the Word of God to them:
*✓* — He gave to some of the Messengers "Thus says the Lord God;" E.g. Ezekiel in the Bible verse above, Moses when sent to Pharaoh, Prophets etc.
*✓* — And to some He gave "It is Written or the Scripture says);" E.g. Teachers, Priests and Judges.
*✓* — And to some others it is like "I see/I saw/I heard (in vision or revelation) this or that or I know/sensed/felt;" E.g. Seers, Visioners, Sensers.
*✓* — And even there are those to whom He gave to expressly say, "I tell you or By my word" as if those Messengers were the Lord God Himself, using their own personal pronouns with authority. For their Words do not fail as the Word of God or to them was given keys of heaven while on earth. E.g. Adam in the Garden, Israel (Jacob) on his dying bed, Samuel the Prophet or the Judge, Elijah (and by extension Elisha), and Simon Peter.
*✓* — And yes, there are those to whom Wisdom and Understanding were given to speak as the Spirit of grace gives them utterance or things to say; and no man can gainsay or trap the wisdom and grace with which they speak so powerfully.
In this Bible verse above, the LORD God was sending the Son of man, Ezekiel, to the obstinate and stubborn children, not with rod or stick to strike them for being stubborn, but with "Thus says the Lord God" only and nothing else such as miracles or working wonders among them. Ezekiel would be the used as the signs among them, as Jonah in the belly of the beast three days was the sign the Lord Jesus gave to those seeking for signs from Him.
Nevertheless, "Thus says the Lord God" is going to do what miracles could not have done, considering all the miracles of Moses compared to just "Thus says the Lord God" that Ezekiel used to raise the dry bones from broken pieces into exceedingly great Army of God. All Moses' miracles only delivered the people out of bondage in Egypt, in the Red sea, and evil wilderness; but those miracles did not raise exceedingly great Army but rebellious and stubborn people. But Ezekiel's thus says the Lord is still Operating even in these last days, raise dry bones into exceedingly great Army even out of their graves. Like John the Baptist who went to prepare the way of the Lord without performing much miracles, and got people (including Pharisees) subscribed to his baptism of repentance for remission of sins.
Ezekiel's "Thus says the Lord" was that which was given to him by God, while Ezekiel beheld or saw God in trance sitted on the Throne and saw the Living Creatures, the Wheels and was powerful endued with the Spirit of God to stand and hear directly from God. Do not joke with such "Thus says the Lord God."