A rough idea of interfaith relations in Hindu texts
These are few verses from the Brahmavaivarta Purana's Krishna-janma-khanda. The context is Vasudeva trying to cool down Kamsa's anger when the latter is about to kill Devaki. Vasudeva says
>वसुदेव उवाच - राजनीतिं न जानासि शृणु मे वचनं हितम्। यशस्करं च दोषघ्नं शास्त्रोक्तं समयोचितम् ॥ अस्या एवाष्टमो गर्भो मृत्युश्चेत्तव भूमिप। इमां च हत्वा दुष्कीर्तिं करोषि त्वं नरः कथम् ॥ वधे च क्षुद्रजन्तूनां हिंसकानां च पण्डितः। कार्षापणं समुत्सृज्य मृत्युकाले प्रमुच्यते॥ अहिंसकानां क्षुद्राणां वधः शतगुणं ध्रुवम् । प्रायश्चित्तं मृत्युकाले कथितं पद्मयोनिना ॥ वधे विशिष्टजन्तूनां पश्चादीनां च कामतः। ततः शतगुणं पापं निश्चितं मनुरब्रवीत् ॥ नराणां म्लेच्छजातीनां वधे शतगुणं ततः। म्लेच्छानां च शतानां च यत्पापं लभते वधे ॥ सच्छूद्रैकस्य च वधे तत्पापं लभते पुमान् ॥ सच्छुद्राणां शतानां च यत्पापं लभते वधे । तत्पापं लभते नूनं गोवधैकेन निश्चितम् ॥ गवां दशगुणं पापं ब्राह्मणस्य वधे भवेत् । विप्रहत्यासमं पापं स्त्रीवधे लभते नरः ॥ विशेषतो हि भगिनी पोष्या च शरणागता । स्त्रीहत्याशतपापं च भवेदस्या वधे नृप॥
Translation : Vasudeva said : You don't know anything about statecraft. Hear from me good words that bring in glory & destroy defects over time. O king ! When her 8th child is destined to kill you, then why do you want to do this bad deed of killing her ? The wise say that on killing aggressive small animals (like snakes & mosquitoes), one gets delivered from the sin during deathbed by donating one karshapana coin (in charity). Killing non-aggrrssive small animals is surely a 100 times more sinful. The penitence is also accordingly designed to be performed at the deathbed by the Lotus-Born One (i.e Brahma). Willingly killing prominent animals and quadrupeds is considered by Manu to be 100 times more sinful (than the preceding case). Killing m*lecchas is considered a 100-times more sinful (than killing animals). A man earns the sin of killing a 100 m*lecchas by killing a single single good shudra. Surely by killing a single cow, one can earn the sin of killing no less than 100 good shudras. Killing a brahmana equivalent to killing 10 cows. A man earns the sin equivalent to killing a brahmana by killing a woman. And this happens to be your own sister, who has been reared under you and has sought refuge under you. O king ! Killing her will be equivalent to killing a 100 women. [Brahmavaivarta Purana:4:7:19-28]
What makes this remarkable is the explicit recognition of the fact that killing non-believers is nothing to be proud about, for it is still a heinous sin. Some might take umbrage at the fact that worth of human life here is being categorised into hierarchies, to which my response is — organising hierarchical structures has always been inherent to human society. Nobody challenged it untill UN Declaration of Human Rights came up with equality of all of humanity. Surely you can't expect an ancient text to confirm to principles developed during the mid 18th century. With that we progress to the next layer
Shukranitisara is a Hindu text dedicated to the statecraft. In the chapter dedicated to royal duties, it states
>ससङ्करचतुर्वर्णा एकत्रैकत्र यवनाः । वेदभिन्नप्रमाणास्ते प्रत्यगुत्तरवासिनः ।। तदाचार्यैश्च तच्छास्त्रं निर्मितं तद्हितार्थकम् ।
Translation: The Yavanas have all the 4 varnas mixed in together, intercaste unions (regularly occur) among them. They live in the North amd the West (of the Indian subcontinent) and follow texts other than the Vedas. They have their own scriptures created by their preceptors for their welfare. [Shukranitisara:4.3:35-36.01]
This is an explicit recognition of legal plurality. In the next chapter, the text then states how to approach this legal plurality
>देशजातिकुलानां च ये धर्माः प्राक् प्रवर्तिताः । तथैवः ते पालनीया प्रजा प्रक्षुभ्यन्तेऽन्यथा ।।
Translation: (The king) should follow the customs in the way they were introduced in the past among various lands, castes and and families, otherwise the subjects get angry. [Shukranitisara:4.5:48]
The fear of popular discontent was such a big factor that even Narada smriti designated पाषण्डनैगमश्रेणीगणधर्मविपर्ययः (i.e. disruption of the customs followed by heretics, communes, organisations and masses) as नृपाश्रय व्यवहार (i.e. judicial procedure that require state intervention), in order to maintain law and order of the land. The same text says
> नाभिशस्तान पतितान द्विषो नापि नास्तिकात्। नावसन्नान्निर्निमित्तां दातारं न प्रपीड्य च॥
Translation: (The king) shouldn't harass those who are hated by the masses, the fallen (excommunicated/apostatised), the public enemy, the non-believers, the distressed and the charitable person without any reason. [Narada smriti:17:40]
So a certain amount of tolerance to people of other faith was sanctioned in the dharmasastra based on the principle of keeping law and order.
Wait should be done in case of violent activities, for example temple desecration
Vishnusmriti says
>प्रतिमाभेदकश्चोत्तमसाहसं दण्ड्य - The breaker of icons is to be punished with the uttama sahasa
The Katyayana smriti says
>हरेद्भिन्द्याद्दहेद्वापि देवानां प्रतिमा यदि । तद्गृहञ्चैव यो भिन्द्यात् प्राप्नुयात् पुर्वसाहसम् ।।
Translation: Those who steal, break or burn divine icons or destroy their residences, receive the punishment under the first sāhasa (i.e the uttama sahasa)
Uttama sahasa is defined as
>वधः सर्वस्वहरणं पुरान्निर्वासनाङ्गके । तदङ्गछेद इत्युक्तो दण्ड उत्तमसाहसे ।।
Translation: Death sentence, confiscation of entire property, banishment from the domain, branding and mutilation of limbs - these are stated to be the punishments inflicted in case of uttama sahasa. [Naradasmriti as quoted as Dandaviveka]
कर्णौष्ठघ्राणपादाक्षिजिह्वाशिश्नकरस्य च । छेदने चोत्तमं दद्याद्भेदने मध्यमं भृगुः ॥
Translation: According to Bhṛgu, amputation of the ears, lips, nose, feet, eyes, tongue, genitals and hands is equivalent to the uttama (sahasa) while only mutilation of the same is equivalent to madhyama (sahasa). [Katyayana smriti as quoted in the Vivadaratnakara].
This definitely shows that whole a certain extent of toleration is sanctioned on the basis of statecraft, abuse of that privilege isn't tolerated, for the tolerance is not based upon equality.