And herein - On this account, accordingly; that is, looking forward to that awful day (compare 2Co 5:10).
I exercise myself - The “I” here is emphatic; “Whatever they do, this is my study.”
to have always a conscience void of offence, etc. - See Act 23:1; 2Co 1:12; 2Co 2:17, etc.; that is, “These are the great principles of my life and conduct - how different from turbulence and sectarianism!”