The meaning of “φυλάσσω”

“The young man saith unto him, All these things have I kept from my youth up: what lack I yet?”

“But he said, Yea rather, blessed are they that hear the word of God, and keep it.”

“As touching the Gentiles which believe, we have written and concluded that they observe no such thing, save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication.”

“For neither they themselves who are circumcised keep the law; but desire to have you circumcised, that they may glory in your flesh.”

“O Timothy, keep that which is committed to thy trust, avoiding profane and vain babblings, and oppositions of science falsely so called:”