In these verses the Lord is commanding us that we shouldn't cast anyone out, or away from our meetings. I don't think any of us would be so brazen to physically kick some one out of a sacrament meeting. But do we sometimes cast people out with our judgements? Or our sideways looks? Or our gossip? Or whisperings? Remember, in Isaiah, the Lord commands us to enlarge our stakes to make our tents (wards) Large enough for anyone who wants to be there. The Savior invites ALL to come unto Him, and we should invite all to come unto His church.