It is said in Vishnudharmottar : The Lord says that one who wears the beads made out of the wood of Tulsi in one’s neck, even if he is untidy and ill- charactered, will undoubtedly attain Me only.
In Garud Purana it is stated: All those people of evil argumentative mentality who say why to wear Tulsi beads, what results are attained by wearing them, and don’t wear Tulsi beads around their neck, burn in the fire of anger of Sri Hari and will never get liberated from hell.
Sri Krishna will grant the fruit of being the resident of Dvarka immediately to those who wear Tulsi beads around the neck. The sins of the person who wears neck beads made of Tulsi with devotion after offering to Sri Vishnu will get vanquished and Devakinandan Sri Krishna will always remain pleased with him, he does not need to undergo further atonement, no more sins remain in his body.
In Kaliyuga, one, who is bedecked with the beads made of Tulsi, performs ritual activities and activities pertaining to ancestors and demigods, obtains crores times more results. The messengers of Yama will flee away by the sight of the Tulsi beads just as leaves are blown off by wind.
In Skanda-puran it is stated :- Those who wear neck beads made of Tulsi after offering it to Sri Hari are definitely foremost among the devotees of Lord. Those fools who wear Tulsi beads without offering to Hari will definitely go to hell. After presenting the mala, it should be purified with panca-gavya; after that the mula-mantra should be recited followed by the recitation of the gayatri mantra for eight times. Touching with incense, worship with this Sadyojata-mantra with utmost devotion: