What is the ruling regarding a Muslim who intends to adopt a Christian child to bring him into Islam, knowing that adoption is forbidden?

Adoption is a pre-Islamic practice that Islam abolished and forbade, in accordance with His, the Almighty's, saying: "Nor has He made your adopted sons your [true] sons. That is [merely] your saying by your mouths, but Allah says the truth, and He guides to the [right] way. Call them by [the names of] their fathers; that is more just in the sight of Allah." It is permissible to sponsor and care for a child without adopting him, to preserve his lineage. If his lineage is unknown, then he is a brother in faith and a mawla, in accordance with His, the Almighty's, saying: "And if you do not know their fathers, then they are your brothers in religion and your protectors."