Brigham Young taught that even in the Millennium, when all shall bow before Christ and accept him as King, people will still be allowed to have agency and choose how they wish to worship:
“They will ask,
‘If I bow the knee and confess that he is that Saviour, the Christ, to the glory of the Father, will you let me go home and be a Presbyterian?’
‘Yes.’
‘And not persecute me?’
‘Never.’
‘Won’t you let me go home and belong to the Greek Church?’
‘Yes.’
‘Will you allow me to be a Friend Quaker, or a Shaking Quaker?’
‘O yes, anything you wish to be, but remember that you must not persecute your neighbors, but must mind your own business, and let your neighbors alone, and let them worship the sun, moon, a white dog, or anything else they please, being mindful that every knee has got to bow and every tongue confess. When you have paid this tribute to the Most High, who created you and preserves you, you may then go and worship what you please, or do what you please, if you do not infringe upon your neighbors.’”
(in Journal of Discourses, 2:317).
Brigham Young also taught that the kingdom of God will be the means of protecting this freedom of worship (see Journal of Discourses, 6:344–45).