SB 3.29.22

yo māṁ sarveṣu bhūteṣu
 santam ātmānam īśvaram
hitvārcāṁ bhajate mauḍhyād
 bhasmany eva juhoti saḥ
Synonyms: 
yaḥ — one who; mām — Me; sarveṣu — in all; bhūteṣu — living entities; santam — being present; ātmānam — the Paramātmā; īśvaram — the Supreme Lord; hitvā — disregarding; arcām — the Deity; bhajate — worships; mauḍhyāt — because of ignorance; bhasmani — into ashes; eva — only; juhoti — offers oblations; saḥ — he.
Translation: 
One who worships the Deity of Godhead in the temples but does not know that the Supreme Lord, as Paramātmā, is situated in every living entity’s heart, must be in ignorance and is compared to one who offers oblations into ashes.
Purport: 

It is stated clearly herein that the Supreme Personality of Godhead, in His plenary expansion of Supersoul, is present in all living entities. The living entities have 8,400,000 different kinds of bodies, and the Supreme Personality of Godhead is living in every body both as the individual soul and as the Supersoul. Since the individual soul is part and parcel of the Supreme Lord, in that sense the Lord is living in every body, and, as Supersoul, the Lord is also present as a witness. In both cases the presence of God in every living entity is essential. Therefore persons who profess to belong to some religious sect but who do not feel the presence of the Supreme Personality of Godhead in every living entity, and everywhere else, are in the mode of ignorance.

If, without this preliminary knowledge of the Lord’s omnipresence, one simply attaches himself to the rituals in a temple, church or mosque, it is as if he were offering butter into ashes rather than into the fire. One offers sacrifices by pouring clarified butter into a fire and chanting Vedic mantras, but even if there are Vedic mantras and all conditions are favorable, if the clarified butter is poured on ashes, then such a sacrifice will be useless. In other words, a devotee should not ignore any living entity. The devotee must know that in every living entity, however insignificant he may be, even in an ant, God is present, and therefore every living entity should be kindly treated and should not be subjected to any violence. In modern civilized society, slaughterhouses are regularly maintained and supported by a certain type of religious principle. But without knowledge of the presence of God in every living entity, any so-called advancement of human civilization, either spiritual or material, is to be understood as being in the mode of ignorance.