In this reading from the Acts of the Apostles, Luke makes two rather intriguing and unexplained remarks: "they had been prevented by the Spirit of the Lord" and "the spirit of Jesus would not allow them." After recounting the man's vision from Macedonia, Luke speaks in a clearer, but undeveloped way: "concluding that God had called us."

These remarks probably refer to some form of the "discernment of spirits". In his First Letter (1 Jn. 4:1), St John urges us to "discern the spirits to see if they come from God." In his letters, St Paul frequently speaks of the Holy Spirit and charismatic gifts in such a way as to imply the need of discernment. The Old Testament speaks of the need to discern between true and false prophets.

In general, the discernment of spirits implies a spiritual maturity, allowing one to evaluate all the interior thoughts, inclinations, tendencies and impulses, which fill our hearts and minds and draw us to greater good, a more liberating love of God, a concerned and caring love of our brothers and sisters, or to the opposite of all that God would desire for us and expect from us.