What is the meaning of "there is no altruism in acts of devotion" or "it is not permissible to give preference to others in acts of worship, but it is permissible in other matters," and is this ruling absolute?

Some scholars said, "There is no īthār (preferring others) in acts of worship," citing the story of the boy who refused to prefer the Prophet, peace and blessings be upon him, with his share. However, the correct view is the permissibility of īthār in acts of worship, and it is a sign of extreme generosity and magnanimity. The Prophet, peace and blessings be upon him, would not have asked the boy for permission if īthār in acts of worship was disliked.