大乘起信論義記 3.471

3.471

This means that the worldly samādhis such as the four dhyānas and four formless attainments, as well as [contemplations of] impurity, ānāpāna, and the like—all samādhis that merely grasp phenomenal marks—are named worldly samādhi. Because one relishes and clings to the realm of samādhi, one is not separated from self; hence it says, 'shared with non-Buddhists.' 'Shared' means that they equally attain this phenomenal samādhi. Because they are shared, if one obtains the protective and assisting power of a good spiritual friend, one may perhaps enter the Buddha-Dharma; if separated from a good friend, one enters heterodox paths.