'Certain' in the Bible

As I urged you when I was on my way to Macedonia, stay on at Ephesus so that you may instruct certain individuals not to teach any different doctrines,

Some individuals have wandered away from these things into empty arguments and useless discussions,

who forbid marriage and advocate abstaining from [certain kinds of] foods which God has created to be gratefully shared by those who believe and have [a clear] knowledge of the truth.