That church and pray'r, and holy Sunday
Were no excuse for sinful Monday;
Thinking in this uncommon mode,
So out of all the priestly road,
What man alive can e'er suppose,
Who marks the way Preferment goes,
That she should ever find her way
To this poor curate's house of clay?
Such was the priest, so strangely wise!
He could not bow — how should he rise?
Learned he was, and deeply read,
But what of that? — not duly bred.
The passage ending "that church....sinful Monday" indicates, satirically(?) that the curate actually had correct ideas as to what it meant to be a pastor and a Christian, e.g. that churchgoing etc on Sunday did not mean that it was OK to be evil on other days of the week.
As he thought so differently from the majority of his fellow clerics, how could anyone expect that he would rise in his profession, i.e. progress beyond the status of curate (assistant that is to a vicar or rector & and on very low salary.)
A scholar he was, but as he did not have the social graces ('he could not bow' i.e. he could not make a graceful bow) he was simply not the type to be promoted. The next passage goes on to say that he had not been to one of the best schools or universities where he would have been able to meet the "right" sort of people to get on.