In the Eleventh Canto of Śrīmad-Bhāgavatam, 40th verse, 11th Chapter, Lord Kṛṣṇa tells Uddhava: "My dear friend, if someone offers Me the best thing in his possession, or anything which is very pleasing to him, he will be eternally benefitted."
In the Nārada-pañcarātra there is a statement of how one can act in all spheres of life for the satisfaction of the Lord. It is stated there that a person who is actually in devotional service must be engaged in all kinds of activities, those prescribed in the revealed scriptures and also those which are accepted for livelihood. In other words, a devotee should engage himself not only in the prescribed duties of devotional service which are mentioned in the revealed scriptures, but he should also perform the duties of his practical life in Kṛṣṇa consciousness. For example, a devotee who has a great establishment, or factory, may offer the fruits of such a material possession for the service of the Lord.
In the Hari-bhakti-vilāsa there is the following statement about self-surrender: "My dear Lord, a person who has surrendered himself unto You, and who is in firm conviction that he is Yours, and actually acts in that way by his body, mind and words, can actually relish transcendental bliss."
In the Nṛsiṁha Purāṇa, Lord Nṛsiṁhadeva says: "Anyone who prays unto Me and takes shelter from Me becomes My ward, and I protect him always from all sorts of calamities."
Serving Trees such as the Tulasī
In the Skanda Purāṇa there is a statement eulogizing the tulasī tree as follows: "Let me offer my respectful obeisances unto the tulasī tree, which can immediately vanquish volumes of sinful activities. Simply by seeing or touching this tree one can become relieved from all distresses and diseases. Simply by offering obeisances to and pouring water on the tulasī tree, one can become freed from the fear of being sent to the court of Yamarāj (the King of death, who punishes the sinful)." If someone sows a tulasī tree somewhere, certainly he becomes devoted to Lord Kṛṣṇa. And when the tulasī leaves are offered in devotion at the lotus feet of Kṛṣṇa, there is the full development of love of Godhead.
In India every Hindu, even those not belonging to the Vaiṣṇava group, take special care of the tulasī tree. Even in great cities where it is very difficult to keep a tulasī tree, people are to be found very carefully keeping this plant. They water it and offer obeisances to it, because worship of the tulasī tree is very important in devotional service.
In the Skanda Purāṇa there is another statement about tulasī, as follows: "Tulasī is auspicious in all respects. Simply by seeing, simply by touching, simply by remembering, simply by praying to, simply by bowing before, simply by hearing about or simply by sowing this tree, there is always auspiciousness. Anyone who comes in touch with the tulasī tree in the above-mentioned ways lives eternally in the Vaikuṇṭha world."