The lectionary is based on scripture - but it occasionally skips a few verses. In most cases this is because they are repetitive and would lengthen the reading while adding little. (This, IMO, seems to be the only case in which the liturgists are interested in shortening the Mass.) The Second reading for Pentecost Sunday is taken from 1 Corinthians 12 and focuses on the Gifts of the Spirit. Different gifts are intended for different persons "for some benefit." The reading, which I will proclaim on Sunday, omits verses 8-10. These verses specify some of the gifts mentioned in 1-7:
To one is given through the Spirit the expression of wisdom; to another the expression of knowledge according to the same Spirit;to another faith by the same Spirit; to another gifts of healing by the one Spirit; to another mighty deeds; to another prophecy; to another discernment of spirits; to another varieties of tongues; to another interpretation of tongues.
All too often, we have a tendency to think that we ought to be exercising the gifts intended for another. We think that the great commission to go out and proclaim the good news should be done in the way some other witness does.
I'm reminded of a letter St. Francis de Sales wrote to a young woman, advising her not to wish to go to Africa and experience glorious martyrdom unless she were able to bear the trials of her present life.