EZEKIEL 1:12
 

And each one went straight forward; they went wherever the spirit wanted to go, and they did not turn when they went. [Ezekiel 1:12 NKJV]
 

And each went straight forward; wherever the spirit was about to go, they would go, without turning as they went. [Ezekiel 1:12 AMP]

These Living Creatures were led by the spirit, and nothing of the flesh led or turned them on. They were not led by money, nor led by materials, nor led by signs and wonders, neither were they led by side attractions: only the spirit led them to wherever the spirit wanted to go. They only go where the spirit wanted to go; and never go where the spirit never wanted to go. And all their goings were straight forward without turning as they go.
 

You don't give instructions to this kind of Living Creatures to control their movement or journey: They do not follow instructions, nor maps, nor navigation, nor command, etc. Rather they go where the spirit would go, not where anyone wants them to go.
 

This means no one sends these Living Creatures errands. Even the spirit do not send these Living Creatures to go anywhere and they go: rather the spirit would go to make them go. If the spirit would not go, the spirit cannot make them to go. 
 

Therefore, do not call these Living Creatures "Messengers" because they are never sent; Rather call these Living Creatures "Escorts" because wherever they go is where the spirit would go. They follow the goings/steps of the spirit, not the sending of the spirit.
 

What acts like them in the physical world even for bit?
 

Your shadow acts like them while following you wherever you go.
 

Who was acting like them in the scriptures even for a bit?
 

Elisha was acting like them while following Elijah in the day Elijah was to be taken to heaven. Elisha was not even taking the instructions from Elijah to wait or to go somewhere else apart from going wherever Elijah was going. As it is written,
 

[2 Kings 2:6] — "And Elijah said to Elisha, “Please stay here, for the LORD has sent me on to the Jordan.” But Elisha replied, “As surely as the LORD lives and as you yourself live, I will not leave you.” So the two of them went on."
 

Again, it is written concerning Ruth after Naomi

[Ruth 1:16-17] — “But Ruth replied: “Do not urge me to leave you or to turn from following you. For wherever you go, I will go, and wherever you live, I will live; your people will be my people, and your God will be my God. Where you die, I will die, and there I will be buried. May the LORD punish me, and ever so severely, if anything but death separates you and me.”