For first of all, when ye come together in the church, I hear that there be divisions among you; and I partly believe it.
First of all. Instead of secondly, follows "therefore," 1 Corinthians 11:20. The "divisions" (Greek, schisms) of opinion (1 Corinthians 1:10) were the PRIMARY evil, causing, at the Lord's supper, their eating apart from brethren (1 Corinthians 11:21) - a secondary evil.
In the church - not the place of worship; for Isidore of Pelusium denies that there were such places set apart for worship in the apostles' times ('Ep.' 246, 2); but 'in the congregation' met for worship, where especially love, order, and harmony should prevail. The very ordinance instituted for uniting believers was made an occasion of "divisions."
Partly - he excepts the innocent. 'I am loath to believe all I hear; but some I am forced to believe, while my love is unaffected by it.'