The topic of worshipping Buddhist relics has been very controversial recently in AF. Apparently the worship of relics has also been an ongoing debate in the Buddhist world for quite a long period of time. I would like to provide more information on this topic based on a paper written by Professor Karel Werner, Honorary Professorial Research Associate in the Department of the Study of Religions, School of Oriental and African Studies, Univ. of London and information from Last Days of the Buddha: The Maha-parinibbana Sutta (revised edition), translated from the Pali by Sister Vajira & Francis Story (Kandy: Buddhist Publication Society, 1998)

What exactly did the Buddha say regarding his relics/body? In the Parinibbāna-sutta (DN XVI), Ananda asked,

katham mayaṁ bhante tathāgatassa sarīre paṭipajjāmā

[How do we act, Sir, with respect to the Tathāgata’s body?]

The Buddha's reply was

avyāvaṭā tumhe ānanda hotha tathāgatassa sarīrapūjāya, iṅgha
tumhe ānanda sadatthe ghaṭatha, sadattham anuyuñjatha, sadatthe
appamattā ātāpino pahitattā viharatha

[Do not concern yourselves, Ānanda, with honouring the
Tathāgata’s body; get on, Ānanda, exert yourselves with respect to
the true goal, dedicate yourselves to the true goal, be heedful of the
true goal, stay zealous and resolute.]

He also added, that various wise nobles, Brahmins and householders would do honour to his body/relics.

25. Then the Venerable Ananda said: "But how, Lord, should they act respecting the body of the Tathagata?"

"After the same manner, Ananda, as towards the body of a universal monarch."

"But how, Lord, do they act respecting the body of a universal monarch?"

26. "The body of a universal monarch, Ananda, is first wrapped round with new linen, and then with teased cotton wool, and so it is done up to five hundred layers of linen and five hundred of cotton wool. When that is done, the body of the universal monarch is placed in an iron oil vessel, which is enclosed in another iron vessel, a funeral pyre is built of all kinds of perfumed woods, and so the body of the universal monarch is burned; and at a crossroads a stupa is raised for the universal monarch. So it is done, Ananda, with the body of a universal monarch. And even, Ananda, as with the body of a universal monarch, so should it be done with the body of the Tathagata; and at a crossroads also a stupa should be raised for the Tathagata. And whosoever shall bring to that place garlands or incense or sandalpaste, or pay reverence, and whose mind becomes calm there — it will be to his well being and happiness for a long time.

27. "There are four persons, Ananda, who are worthy of a stupa. Who are those four? A Tathagata, an Arahant, a Fully Enlightened One is worthy of a stupa; so also is a Paccekabuddha, and a disciple of a Tathagata, and a universal monarch.

28-31. "And why, Ananda, is a Tathagata, an Arahant, a Fully Enlightened One worthy of a stupa? Because, Ananda, at the thought: 'This is the stupa of that Blessed One, Arahant, Fully Enlightened One!' the hearts of many people will be calmed and made happy; and so calmed and with their minds established in faith therein, at the breaking up of the body, after death, they will be reborn in a realm of heavenly happiness. And so also at the thought: 'This is the stupa of that Paccekabuddha!' or 'This is the stupa of a disciple of that Tathagata, Arahant, Fully Enlightened One!' or 'This is the stupa of that righteous monarch who ruled according to Dhamma!' — the hearts of many people are calmed and made happy; and so calmed and with their minds established in faith therein, at the breaking up of the body, after death, they will be reborn in a realm of heavenly happiness. And it is because of this, Ananda, that these four persons are worthy of a stupa."

It is very clear then, that relics should be kept in a stupa for veneration. The Buddha also highlights the fact that stupas are to inspire faith in people, so as to allow them to cultivate a calm and happy mind, leading to a good rebirth after death. This is the reason for the establishment of stupas or the reason for the veneration of relics.

The Buddha did not say that his relics should be worn, or that it grants people who possess or wear them supernatural powers or miracles at all. My personal opinion is that someone who wears relics, should be always aware of his thoughts and deeds, making sure he observes the 5 precepts at all times. If he does not, then he should not be wearing relics.

Na kho ānanda ettāvatā tathāgato sakkato vā hoti garukato vā
mānito vā pūjito vā apacito vā yo kho ānanda bhikkhu vā bhikkhunī
vā upāsako vā upāsikā vā dhammānudhamma paṭipanno viharati
samīci paṭipanno anudhamma cārī so tathāgataṁ sakkaroti garukaroti
māneti pūjeti paramāya pūjāya tasmāt ih’ānanda dhammānudhamma
paṭipannā viharissāma samīci paṭipannā anudhamma cārino ti evaṁ
hi vo ānanda sikkhitabban ti

[Not really thus, Ananda, is the Tathāgata fully honoured, revered,
highly regarded, venerated, esteemed. Whichever monk or nun or lay
male or female follower who, having embarked on the path to truth,
lives in conformity with truth, has entered upon the proper course,
walks in harmony with truth, [such a one] truly honours, reveres,
highly regards, venerates Tathāgata with the highest homage.
Therefore, Ānanda, live in conformity with truth, follow the proper
course, walk in harmony with truth. Thus, Ānanda, should it be
taught.]

The conclusion of Prof Werner is this:

This is, the Buddha clearly says, how the message should be taught to all regardless of status. Embark on the path to freedom and persevere until the goal is reached. But since this is not an injunction or formal setting of a vinaya rule, it neither excludes nor forbids worship or salutation (pūjā or vandanā) of the Buddha’s body or relics. But it goes without saying that these acts do not lead to liberation, although they may secure a favourable rebirth within the confines of saṁsāra, albeit with its intrinsic danger of straying away from the true path. This is the point at which, when it is understood, a choice is made.