It is necessary - Berry's New Testament Synonyms

It is necessary

δεῖ, ὀφείλω.

δεῖ, the third person of δέω, is commonly used impersonally in classical Greek. This usage is less common, but frequent, in the N.T. δεῖ indicates a necessity in the nature of things rather than a personal obligation, it describes that which must be done. ὀφείλω indicates rather the personal obligation, it is that which is proper, something that ought to be done.