A certain King advertised, and sent out invitations, for volunteers to go on a special mission into foreign lands to represent his Royal interests. No salary was offered. Most of his subjects were too busy with their own interests and income to volunteer. They didn't trust their King to treat them fairly and reward them for their service. He would deal with their distrust later.
Among the volunteers were a few who were so sick of themselves, and so loved the King that they were more concerned with his interests than their own, but knew that if they looked after his interests he would look after theirs. Their main concern was to please their King and do his Royal will. They trusted in him.
Also among the volunteers were some who didn't want the job but were afraid not to volunteer lest the King seek vengeance upon them. Others were so bored with their present life, husband or wife that they volunteered on the chance they might be happier somewhere else or find a new, more desirable mate. Then, there were those volunteers who wanted a free vacation with new acquaintances in a different environment. Some thought volunteering might strengthen their resume or that they might meet new prospective customers for their own business if they joined the King's service. A few even thought that if they volunteered, the King might drop all criminal charges against them so they could avoid His judgement and remain free to do their own thing.
What none of them knew was that the King had a divine, super computer program containing all of the knowledge in all of the libraries and public records and in all of the universe about everything and everybody ... including them. He knew each of them better than they knew themselves.
So, on a day appointed, all the volunteers, sincere and insincere, came before the King as a volunteer. As he passed before each of them, he "selected" one here and one there according to his "foreknowledge" of each and every one of the volunteers. He set those he chose, selected and elected aside for training in the King's service. They were first sent to the Royal Bath, cleaned up, groomed and properly attired. They were then sent to their studies of the Royal Manuscripts and thoroughly prepared to represent the King all over the world.
The English word "select" is from the Latin word "selectus" and means to elect or "select aside" or "set aside" for special reasons... or to "separate the chosen from all those not chosen". "Sanctification" is the same thing.
It has not been determined which came first, Latin or Greek, but each has formed with root words in the other. English has absorbed many words from both.
Jesus used the word "sanctified" in His prayer concerning those he selected, elected and chose: Bear in mind the Greek word "hagiazo" translated "sanctify" in the New Testament, means "to set apart". Jesus prayed for his disciples in Bible days and also for His "set apart", chosen ones of today, in John 17:15-20.
"I pray not that thou shouldest take them out of the world, but that thou shouldest keep them from the evil. They are not of the world, even as I am not of the world. Sanctify them through thy truth: thy word is truth. As thou hast sent me into the world, even so have I also sent them into the world. And for their sakes I sanctify myself, that they also might be sanctified through the truth. Neither pray I for these alone, but for them also which shall believe on me through their word."
"Wherefore (YOU) come out from among them, and be ye separate, saith the Lord ...." 2Cor.6:17.
You may not yet be among those chosen, selected, elected or sanctified but if you are sincere and desire to serve the King, you must first be among the volunteers. He will not force you into His service, but said, "Come unto Me." John 7:37.