The quote “One mustn’t criticize other people on grounds where he can’t stand perpendicular himself” essentially means that one should not criticize others for faults or weaknesses that they themselves possess. The term “stand perpendicular” is metaphorical for standing upright or being perfect in a particular aspect. Therefore, if one is not perfect or upright in a certain area, they do not have the moral authority or credibility to criticize others for the same faults.

This quote is a timeless reminder of the importance of self-awareness and humility. It is a call to introspection before judging others. It’s easy to point out other people’s flaws without realizing that we may be guilty of the same. This is a form of hypocrisy, and it’s something that the quote warns against.

In today’s world, this quote is incredibly relevant. With the rise of social media, people are quick to judge and criticize others publicly. Often, these criticisms come from a place of self-righteousness, without any self-reflection on whether they themselves might be guilty of the same faults they are criticizing.

In terms of personal development, this quote can be a guiding principle. It encourages us to focus on improving ourselves rather than judging others. It’s about recognizing our own flaws and working on them, rather than projecting them onto others. It’s a reminder that no one is perfect, and we all have areas where we can’t “stand perpendicular.” Therefore, we should be understanding and compassionate towards others’ imperfections, just as we would want them to be towards ours.

In essence, the quote is a call to self-improvement, empathy, and understanding, rather than judgment and criticism of others. It reminds us to be humble and self-aware, and to strive for personal growth rather than focusing on the flaws of others.