O God, whose blessed Son became poor that we through his poverty might be rich: Deliver us, we pray thee, from an inordinate love of this world, that inspired by the devotion of thy servant Sergius of Moscow, we may serve thee with singleness of heart, and attain to the riches of the age to come; through the same Jesus Christ our Lord, who liveth and reigneth with thee and the Holy Spirit, one God, now and for ever.
Ah, so many saints, so little time to work out who they all are.
I am guessing that this post refers to [url=http://ocafs.oca.org/FeastSaintsViewer.asp]Saint Sergius of Radonezh[/url] as he is the only Sergius I found commemorated today.