'Essential' in the Bible

For it seemed good to the Holy Spirit and to us not to place on you any burden but these essential requirements:

I therefore strongly advise you to take some food. This is essential for your safety. For not a hair will perish from the head of any one of you."

They show that the essential requirements of the Law are written in their hearts; and their conscience [their sense of right and wrong, their moral choices] bearing witness and their thoughts alternately accusing or perhaps defending them

and know His will and approve the things that are essential, being instructed out of the Law,

an educator of the senseless, a teacher of little children, because you have in the law the essential features of knowledge and of the truth --

On the contrary, those members that seem to be weaker are essential,

For if I [or anyone else should] rebuild [through word or by practice] what I once tore down [the belief that observing the Law is essential for salvation], I prove myself to be a transgressor.

yet to remain in my body is more necessary and essential for your sake.

Therefore, it was essential that He had to be made like His brothers (mankind) in every respect, so that He might [by experience] become a merciful and faithful High Priest in things related to God, to make atonement (propitiation) for the people’s sins [thereby wiping away the sin, satisfying divine justice, and providing a way of reconciliation between God and mankind].

For every high priest is appointed to offer both gifts and sacrifices; so it is essential for this One also to have something to offer.

By this we know [and have come to understand the depth and essence of His precious] love: that He [willingly] laid down His life for us [because He loved us]. And we ought to lay down our lives for the believers.