James 1:4

But let patience have her perfect work Better, and let endurance have a perfect work, there being sequence of thought but not contrast. The word for "perfect" expresses the perfection of that which reaches its end, and so implies, possibly, a reference to our Lord's words in Matthew 10:22. The form of the counsel implies that the work might be hindered unless the will of those who were called to suffer co-operated with the Divine purpose. The sufferings must be borne joyfully as well as submissively.

that ye may be perfect and entire The latter word implies completeness in all parts or regions of the spiritual life, as the former does the attainment of the end, the completeness of growth. The corresponding substantive is used for the "perfect soundness" of the restored cripple in Acts 3:16; the adjective, in a like spiritual application, in 1 Thessalonians 5:23.

wanting nothing The English is unfortunately ambiguous. Better, failing or lacking in nothing.