CC Ādi 1.92
যাহা হৈতে কৃষ্ণভক্তি হয় অন্তর্দ্ধান ॥ ৯২ ॥
yāhā haite kṛṣṇa-bhakti haya antardhāna
The foremost process of cheating is to desire to achieve liberation by merging into the Supreme, for this causes the permanent disappearance of loving service to Kṛṣṇa.
The desire to merge into the impersonal Brahman is the subtlest type of atheism. As soon as such atheism, disguised in the dress of liberation, is encouraged, one becomes completely unable to traverse the path of devotional service to the Supreme Personality of Godhead.