'Necessary' in the Bible

Because of this, [it is] all the more necessary [that] we pay attention to the [things] we have heard, lest we drift away.

For it was fitting for God [that is, an act worthy of His divine nature] that He, for whose sake are all things, and through whom are all things, in bringing many sons to glory, should make the author and founder of their salvation perfect through suffering [bringing to maturity the human experience necessary for Him to be perfectly equipped for His office as High Priest].

Because of this it was necessary for him to be made like his brothers in every way, so that he might be a high priest full of mercy and keeping faith in everything to do with God, making offerings for the sins of the people.

Now if perfection [a perfect fellowship between God and the worshiper] had been attained through the Levitical priesthood (for under it the people were given the Law) what further need was there for another and different kind of priest to arise, one in the manner of Melchizedek, rather than one appointed to the order of Aaron?

Because if the priests are changed, it is necessary to make a change in the law.

For every high priest is appointed to offer gifts and sacrifices; therefore it was necessary for this priest also to have something to offer.

“And it will not be [necessary] for each one to teach his fellow citizen,Or each one his brother, saying, ‘Know [by experience, have knowledge of] the Lord,’For all will know [Me by experience and have knowledge of] Me,From the least to the greatest of them.

for where a covenant is, the death of the covenant-victim to come in is necessary,

It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these.

since it would have been necessary for him to suffer many times from the foundation of the world, but now he has appeared once at the end of the ages for the removal of sin by the sacrifice of himself.

And every priest takes his place at the altar day by day, doing what is necessary, and making again and again the same offerings which are never able to take away sins.

And without faith it is not possible to be well-pleasing to him, for it is necessary for anyone who comes to God to have the belief that God is, and that he is a rewarder of all those who make a serious search for him.