坐禪三昧經 1.75

1.75

復次，若心不悅，勸勉令喜。心作攝時，亦念息入出——設心不定，強伏令定。如經中說：「心定是道，心散非道。」心作解脫時，亦念息入出——若意不解，強伏令解。譬如羊入蒼耳，蒼耳著身，人為漸漸出之。心作解脫諸煩惱結，亦復如是！是名心念止作解脫。

"Furthermore, if the mind is not delighted, one encourages it to make it joyful. When the mind is collected, one is also mindful of the breath entering and exiting: if the mind is unsettled, one forcefully subdues it to make it settled. As it is said in a sūtra: 'A settled mind is the path; a scattered mind is not the path.' When the mind is liberated, one is also mindful of the breath entering and exiting: if the mind is not liberated, one forcefully subdues it to make it liberated. It is like a sheep entering cockleburs: the cockleburs cling to its body, and a person gradually removes them for it. The mind liberating itself from all the bonds of kleśas is also like this! This is called attaining liberation in mindfulness of the mind."