en_tn/eph/04/16.md

into him who is the head ... makes the body grow so that it builds itself up in love

Paul uses the human body to describe how Christ causes believers to work together in harmony as the head of a body causes the body parts to work together to grow healthy. (See: rc://en/ta/man/translate/figs-metaphor)

by every supporting ligament

A "ligament" is a strong band that connects bones or organs in place in the body.