'Assistant' in the Bible

Now Herod was having an angry quarrel with the people of Tyre and Sidon. So they joined together and presented themselves before him. And after convincing Blastus, the king's personal assistant, to help them, they asked for peace, because their country's food supply was provided by the king's country.

Arriving in Salamis, they proclaimed God’s message in the Jewish synagogues. They also had John as their assistant.

As to all my affairs, Tychicus, who is a much-loved brother and faithful assistant and fellow bond-servant in the Lord, will give you all the information.