Meditative concentration (samādhi) is the mark of accomplishment in dharma practice

Answer: Each of the sixteen contemplations in the Contemplation of the Buddha of Immeasurable Life Sutra is only considered complete once samādhi has manifested; after that, one may proceed to the next contemplative practice. The first contemplation, the sun contemplation, requires the manifestation of samādhi—the setting-sun samādhi—wherein the image of the setting sun continuously appears in the mind without ceasing, and both body and mind abide in a state of meditative concentration, free of afflictions and scattered thoughts. Apart from sleep, one remains in samādhi at all times; only then is the sun contemplation samādhi complete, and one may proceed to the second contemplation. In cultivating any dharma and realizing any path, including meditative concentration and wisdom, if samādhi does not manifest, the cultivation cannot be considered successful, nor can it be counted as realizing the dharma or realizing the path. In the period before and after samādhi manifests, sleep is no longer heavy; there are no scattered or chaotic dreams, and the mind possesses a certain degree of clarity. Sleep is brief and light, without dullness. In light sleep there should still be images; in deep sleep, they are gone.

We have been practicing the sun contemplation in our group for three years now, haven't we? Not a single person has succeeded in it—and this is the simplest and easiest of the contemplative practices. Clearly, cultivation is not such a simple matter, especially the attainment of great wisdom such as the elimination of self-view and awakening to the true mind and seeing one's nature—these are even less easily accomplished. Of the sixteen contemplations in the Contemplation of the Buddha of Immeasurable Life Sutra, only by accomplishing the third contemplation can one be assured of rebirth in the land of bliss (Sukhāvatī) at the end of life; only by reaching the seventh contemplation can one awaken to the true mind and attain enlightenment. In three years, no one has accomplished even the first contemplation—by what year and month could the third and seventh contemplations be accomplished? Cultivation is by no means easy, unless one practiced it in past lives and was already an accomplished practitioner; only then is it somewhat easier in this life.