CC Ādi 13.70
kṛṣṇa-pūjā kare tulasī-gaṅgājala diyā
Tulasī leaves and Ganges water, with, if possible, a little pulp of sandalwood, is sufficient paraphernalia to worship the Supreme Personality of Godhead. The Lord says in the Bhagavad-gītā (9.26):
patraṁ puṣpaṁ phalaṁ toyaṁ yo me bhaktyā prayacchati
tad ahaṁ bhakty-upahṛtam aśnāmi prayatātmanaḥ
“If one offers Me with love and devotion a leaf, a flower, a fruit or water, I will accept it.” Following this principle, Advaita Prabhu pleased the Supreme Personality of Godhead with tulasī leaves and water of the Ganges.