Yajña in the Bhagavad-gītā
3.12
The devotees of the Lord are released from all kinds of sins because they eat food that is offered first for sacrifice. Others, who prepare food for personal sense enjoyment, verily eat only sin.
4.30-31
One must follow the vow (i.e. perform yajña) to please Kṛṣṇa.
3.25
Even if on an elevated platform, a devotee follows the rules of yajña to teach by example.
Principles of offering
You must offer everything before you eat.
1. Frees you from the modes
2. Regenerates your body
3. Purifies your consciousness
You must approach Kṛṣṇa through the spiritual master.
1. Dāsa dāsa anu dāsa.
2. We are assisting the spiritual master in offering. (And my spiritual master is assisting his spiritual master, etc.)
Your offerings must be personal (Attention to detail indicates seriousness and personal-ness.)
1. Offerings should include Tulasi
2. One should offer personal prayers from the heart. (Not mechanically.)
3. Offerings should be done in an atmosphere of cleanliness.
a. a restaurant, if someone finds a hair in their food, it’s a scandal.
Punctuality:
1. Every household has a schedule. According to your own schedule, regularly offer your food to Kṛṣṇa.
2. Don’t be lazy
Prasadam pastimes
By his loving, ecstatic mood Nṛsiṁhānanda Brahmacāri through meditation attracted Lord Gaurasundara to eat his offerings. Cc Antya 2.35-83
Raghunātha Dāsa Goswāmī
Lord Caitanyā relished the rotten rice of Raghunātha Dāsa Goswāmī because it was from his pure devotee. Cc Antya 6.310-329
Advaita Ācarya’s loud cries and offering of Tulasi leaves attracted the Lord to descend. Cc Ādi 3.92-114