What is the ruling on placing the ring on the bride's hand in her home before the wedding?

Wearing an engagement ring is a custom of the Christians, which is forbidden for a Muslim to do. It also involves another sin, which is the suitor touching the hand of his fiancée and vice-versa. The Prophet, peace and blessings be upon him, said: "For one of you to be stabbed in the head with an iron needle is better for him than that he should touch a woman who is not lawful for him." However, if this occurs after a valid marriage contract, then there is no harm in touching her, but the issue of imitating disbelievers remains.