The Spirit himself becomes visible in every gift that he gives. This is what is conveyed by the term manifestation of the Spirit.
The words for the common good
are key to a proper understanding of the spiritual gifts (see also Ephesians 4:12–16) and to Paul’s entire argument in 1 Corinthians 12:1 – 14:40. It seems that there was a tendency in the Corinthian church to approach spiritual gifts in a prideful and self-absorbed manner. Paul will continually remind them that spiritual gifts are meant to build up the church.
7 To each is given the manifestation of the Spirit for the common good.