Concentrate! Persevere!
When we investigate Chan, we should not fear backaches and pain in our legs. We must draw on our vajra will and use patience and perseverance to investigate Chan. We must constantly persevere and be firm and uncompromising in our resolve. In every moment, we must practice hard.

In the past, virtuous elders in the monastic Sangha, having practiced sitting meditation for many years, continued to sit. This shows that cultivation is not so simple and easy. We must endure. We cannot pluck a lotus blossom today and pick a peony tomorrow. We should not think that by sitting for a day we can become enlightened. We need to understand the importance of patience when practicing Chan sitting.

How do we concentrate? Well, imagine the intensity with which a young girl pursues a boy she likes, or how a boy chases a girl. That is how concentrated we should be in meditation. If we can be that determined and intent on our investigation of Chan, so that we are ever-mindful of the present, then there is no reason why we cannot succeed.