Matthew 7:1. Judge not, that you be not judged.  2. For with the judgment you pronounce you will be judged, and the measure you give will be the measure you get.

…To keep this sermon from becoming a stumbling block and being misunderstood as if it forbade any judgment or criticism at all, it should be clear, on the basis of what has already been said so often, that here Christ is preaching only to His disciples. He is not talking at all about the judgment or punishment that takes place in the world. In the household, for example, the mother and father have to judge among the children and the servants, have to administer punishment, even corporal punishment, when they refuse to behave. If a prince or a judge wants to administer his office properly, he cannot avoid judging and punishing. This is all part of the secular realm, which is not our concern here and which we will therefore permit to act the way it should and must act. What we are discussing here is another kingdom, one which in no way weakens or annuls the other, namely, spiritual life and existence among Christians, where it is forbidden for one to judge and condemn another. The devil always mixes into such judging to do his work. He gives each individual a high estimate of himself and the opinion that his cause must be the best and must be the only one to prevail, while he criticizes and undermines whatever does not measure up to his standards.  (Luther’s Works, v. 21, pages 210-211).

It must not be this way among Christians. Those who have honest and pious hearts should highly esteem their ministers and preachers in all humility and love, for the sake of Christ and of His Word. They should regard them highly as a gift and jewel given by God, more precious than any temporal treasure or possession. Similarly, true and pious preachers will faithfully seek only the welfare and the salvation of all people. They will not impose any burden on them, either in their consciences or even outwardly in their temporal possessions and physical existence. Whoever despises them should know that he is not a Christian and that he has lost the treasure once more. Our preaching and admonition is for everyone who will accept it and agree with us. Whoever refuses to do so and yet uses the name of the Gospel or the pretense of Christian brotherhood to despise us and to trample us underfoot, against him we use the art of letting him keep the pretense but actually taking everything back, so that he has nothing left at all. We have the command to separate ourselves from such people. We do not enjoy doing it, and we would have preferred to have them stay with us. But since they refuse, we must let them go and not let them ruin our treasure or trample it underfoot.  (Luther’s Works, v. 21, pages 228).