'Zealous' in the Bible

We have sent with them our brother, whom we have often tested and found to be diligent in many things, but who is now even more diligent [than ever] because of his great confidence in you.

I am jealous for you with a godly jealousy because I have promised you to one husband, to present you as a pure virgin to Christ.

And [you have heard how] I surpassed many of my contemporaries among my countrymen in [my advanced study of the laws of] Judaism, as I was extremely loyal to the traditions of my ancestors.

Let us therefore make every effort to enter that rest [of God, to know and experience it for ourselves], so that no one will fall by following the same example of disobedience [as those who died in the wilderness].

Now who is there to hurt you if you become enthusiastic for what is good?