The phrase "get up" is being taken from the Greek word ἐγείρω (egeirō), which means "to arouse" and "cause to rise" but also to "to cause to appear, bring before the public" according to Thayer's lexicon.
The time of death
Why is this important? Because it was not as if the dead body was sleeping and being woken up. When the body dies, the spirit-person leaves the physical body. The first stage - confirmed by hundreds of thousands of clinical-death cases - is that the spirit-person will rise above the physical body and look down upon it.
During this time the spirit-person also sees many things going on around the body. The spirit-person may also be grieving his departure from his family members and be hanging on, trying to contact them.
And depending upon the circumstances of the person's death - for example in the case of suicide or substance overdose where the person artificially cut short their ordained lifespan - that "unembodied" period may last for years.
What does this have to do with Jesus' "raising the dead" with this young man? Because Jesus was not waking a sleeping person as is supposed by this translation. He was commanding the spirit-person who just left that body to come back into the body.
This might be compared to a person who is revived in the hospital in urgent care. As they are revived, the spirit-person is drawn back into the body. In some cases, during their after-clinical death period, the person reports being told by a higher authority it is not "their time" yet.
So we find here that Jesus was able to interact with the realm of the subtle physical dimension as well as the realm of the spirit-person, and bring that spirit-person back into their body.
How does Jesus have this ability?
The Supreme Being. God is the Master of all dimensions, including the physical dimension and the subtle physical dimension. The Supreme Being may empower His loving servants with authority to work within these dimensions at will.
Jesus is God's representative. This has been shown throughout the Gospels, and stated clearly by Jesus many times, including:
"For I have come down from heaven not to do my will but to do the will of Him who sent me." (John 6:38)Coming "down from heaven" means appearing in the gross and subtle physical dimensions. And coming "to do the will of Him who sent me" means the purpose of Jesus' appearance was to act on behalf of the Supreme Being. Thus we can see that Jesus was God's representative. He was authorized by the Supreme Being.
And what was the purpose of Jesus' appearance? Better yet, what is God's will that Jesus is referring to here? It is centered around Jesus' teachings. This is why Jesus traveled by foot to so many towns like Nain to teach what God wanted him to teach:
"My teaching is not my own. It comes from the One who sent me." (John 7:16)Those teachings relate to bringing us back home. Jesus came to teach love for God and show us how we can devote our lives to the Supreme Being, and at the end of this physical lifetime, leave these temporary physical bodies and return to our home in the spiritual world.
How then does this purpose relate to 'raising' someone from the 'dead' - bringing this spirit-person back into their physical body? Jesus was trying to illustrate that we live on after the body dies. He was also illustrating his God-given authority. He was trying to show them that he indeed was representing the Supreme Being. During the culture of those times, healings were expected from those with authority. In order to do God's will and give them God's teachings, Jesus performed a few miracles to encourage people to hear those teachings - and trust those teachings.
And what was the sum and substance of those teachings?
“ ‘Love the Lord your God with all your heart and with all your soul and with all your mind.' This is the first and greatest commandment.” (Matt. 22:37-38)