Is the principle “Be strict with self and lenient with others” a biblical principle? But if I am convinced that doing something (or not doing it) is biblical / correct, should I then not expect others to do it too? After all, it is good for them, and for the church. On top of that I am my brother’s keeper and have to provoke them unto good works.

I do believe that the principle you stated is a biblical principle. It is true that we will not be able to find this principle stated in that many words in the Scriptures, but it will not be difficult, I believe, for us to show that it is scriptural.

In the first place, the Lord reveals our hypocritical tendencies when He asks: “And why beholdest thou the mote that is in thy brother’s eye, but considerest not the beam that is in thine own eye?” (Mt 7:3). The fact is that most of us are by nature blind to our own faults, whereas we see the faults of others glaringly. A principle which helps counteract this tendency, which does not contradict any other biblical principles, cannot be wrong.

In the second place, the Apostle Paul teaches us, in a number of places, that we should consider others better than ourselves: “Let nothing be done through strife or vainglory; but in lowliness of mind let each esteem other better than themselves” (Phil 2:3). “Be kindly affectioned one to another with brotherly love; in honour preferring one another” (Rom 12:10). How can we esteem others better than ourselves or prefer others in honour without hypocritical flattery, but that we first learn to see ourselves more critically than we see others.

Notice that the advice of Paul is almost the reverse side of what the Lord teaches in Matthew 7:1–5. The Lord’s instruction is that we should not be quick to judge others negatively. Paul’s instruction is that we should always seek to judge others positively. Being strict with self and lenient with others simply facilitate obedience to these two commandments.

But how do we reconcile this principle with the fact that we have a duty to warn others of their sin? The Scripture does, indeed, teach us that if we are in a position to admonish someone when he sins, but fails to do so, then we would also have to bear part of the responsibility of the person’s sin (Ezk 3:18–19; Ps 50:18–19; 1 Tim 5:22). And besides this, the Scripture strongly condemns those who call evil good (Isa 5:20). The problem is if we have to be more lenient with others, how can we admonish them for their sins?

The answer is actually quite obvious if you think about it. Notice that both instructions, pertaining to our judgement of others (from which we derive the principle that we should be stricter with ourselves but more lenient with others), speak of judgement relatively only in respect to our own righteousness or honour, but not in respect to God’s absolute standard. In other words, we must be ready to point out errors and sin (Jas 5:19–20), but we must do so with charity, “charity shall cover the multitude of sins” (1 Pet 4:8). That is to say also, that before we admonish anyone for their sin, we must also consider that we have also likewise sinned and have found forgiveness in Christ, so that we may be ready to forgive too (Mt 6:12, 14–15; Eph 4:32). That is also to say that before we admonish anyone, we must first consider any mitigating factor, which might have contributed to the fault. Sin will remain sin, but we must admonish differently according to the circumstance that the person is in. The Lord Jesus dealt very compassionately with the women caught in adultery (Jn 8:1–11); but in the same chapter, He condemns the unbelieving Jews as being children of the devil (Jn 8:44).

Now, of course we do not have in our possession omniscience, or the ability to perceive the thoughts of others, which the Lord had, and therefore, the principle of being stricter with ourselves and more lenient with others would dictate that, firstly, we have to take the reasons and excuses of others at face value and, secondly, that we must try not to impose our standards upon others.

Thus, for example, if you wish to admonish a brother for habitual lateness, you must never compare yourself with him, and say (or think): “See, I have children too, but I can come early, why can’t you? In fact, I live further than you, and I don’t drive, and yet I can come on time.” If you do so, you would have violated the principle of esteeming others better than yourself and of being stricter with yourself and more lenient with others. You should rather approach the brother with charity, understanding that he may have difficulties, which you are not aware of, which he may or may not share with you; and understanding also that he may not be as able to handle the difficulties as you.

Bear in mind, however, that this is a principle of personal relationship one with another. We should never apply this principle to the preacher and say that he should not condemn sin so strongly. The preacher and pastor ought to preach against sin without mitigation, without fear or favour of man, because he is preaching the Word of God, and it is impossible for him to enumerate in minute details the circumstances surrounding a particular sin. He should rather speak to the conscience and leave the application of the Word to the Holy Spirit to convict or comfort as the case may be. But in person, he must also apply the principle of personal relationships as much as possible. This is perhaps the reason why it is said of the Apostle Paul: “His letters,… are weighty and powerful; but his bodily presence is weak, and his speech contemptible” (2 Cor 10:10).