What does Luke 15:27 mean?

An eldest son, the heir of his father, has come in from working in the fields. He approaches the house and hears dancing music. He asks a servant what is going on. The servant explains that the son's younger brother, who years ago had disgraced the family, taken his inheritance, and ran far away, has returned. In celebration, their father welcomed him wholeheartedly. The younger son now wears a ring and the best robe. In addition, the father has killed the calf kept for the greatest celebrations and invited everyone to share his joy (Luke 15:11–26).

The term hygiainonta is from a root word referring to health or wholeness. It is also used poetically to mean something free from error. The younger son is likely not in great health. He left after nearly starving during a famine and has been traveling since. But he is alive. And yet, the younger son is indeed "free from error." He arrived with a new understanding of what he had done. He had sinned against God and his father. He was no longer worthy to be his father's son. He arrived in humble repentance, intending to beg to serve his father like a hired laborer.

This change in understanding is the repentance God seeks from all of us. To repent is to recognize our sinful state, understand we are wrong and God is right, and desire to be reconciled to God. With this repentance, our relationship with God, like the younger son's relationship with his father, is sound. God covers us in Christ's holiness as if it were our own like the father covered his son with the best robe (Isaiah 61:10). Our spiritual life is made sound. God gives us everlasting life so that we can be empowered by the Holy Spirit and live with Him forever (John 1:12).