'Necessary' in the Bible

I did not take you with me when I went away from Crete, so that you might do what was necessary to put things in order there, placing men in authority over the churches in every town, as I said to you;

For it is necessary [for] the overseer to be blameless as God's steward, not self-willed, not quick-tempered, not addicted to wine, not violent, not greedy for dishonest gain,

It is necessary to silence them; they overthrow whole households by teaching what they shouldn’t in order to get money dishonestly.

And let ours also learn to maintain good works for necessary uses, that they be not unfruitful.