Shunryu Suzuki said this quote

“ It is said that there are four kinds of horses: excellent ones, good ones, poor ones, and bad ones. The best horse will run slow and fast, right and left, at the driver’s will, before it sees the shadow of the whip; the second best will run as well as the first one does, just before the whip reaches its skin; the third one will run when it feels pain on its body; the fourth will run after the pain penetrates to the marrow of its bones. You can imagine how difficult it is for the fourth one to learn how to run!When we hear this story, almost all of us want to be the best horse. If it is impossible to be the best one, we want to be the second best. That is, I think, the usual understanding of this story, and of Zen. You may think that when you sit in zazen you will find out whether you are one of the best horses or one of the worst ones. Here, however, there is a misunderstanding of Zen. If you think the aim of Zen practice is to train you to become one of the best horses, you will have a big problem. This is not the right understanding. If you practice Zen in the right way it does not matter whether you are the best horse or the worst one. When you consider the mercy of Buddha, how do you think Buddha will feel about the four kinds of horses? He will have more sympathy for the worst one than for the best one.When you are determined to practice zazen with the great mind of Buddha, you will find the worst horse is the most valuable one. In your very imperfections you will find the basis for your firm, way-seeking mind. Those who can sit perfectly physically usually take more time to obtain the true way of Zen, the actual feeling of Zen, the marrow of Zen. But those who find great difficulties in practicing Zen will find more meaning in it. So I think that sometimes the best horse may be the worst horse, and the worst horse can be the best one.If you study calligraphy you will find that those who are not so clever usually become the best calligraphers. Those who are very clever with their hands often encounter great difficulty after they have reached a certain stage. This is also true in art and in Zen. It is true in life. So when we talk about Zen we cannot say, 'He is good,' or 'He is bad,' in the ordinary sense of the words. The posture taken in zazen is not the same for each of us. For some it may be impossible to take the cross-legged posture. But even though you cannot take the right posture, when you arouse your real, way-seeking mind, you can practice Zen in its true sense. Actually it is easier for those who have difficulties in sitting to arouse the true way-seeking mind that for those who can sit easily. ”