Engagement according to sharee'ah means that the man asks the woman to marry him. The view of the scholars is that engagement is prescribed for one who wants to get married. Allaah says (interpretation of the meaning):

"And there is no sin on you if you make a hint of betrothal…"

[al-Baqarah 2:235]

and it was narrated that the Prophet (Peace And Blessings Of Allaah Be Upon Him) got engaged to 'Aa'ishah. (Al-Bukhaari, al-Nikaah, 4793). And in al-Saheeh it also states that the Messenger (Peace And Blessings Of Allaah Be Upon Him) got engaged to Hafsah. (Al-Bukhaari, al-Nikaah, 4830).

The Messenger of Allaah (Peace And Blessings Of Allaah Be Upon Him) encouraged the one who wants to get engaged to look at the woman to whom he wishes to propose. According to the hadeeth, "When any one of you proposes marriage to a woman, if he can look at that which will encourage him to go ahead and marry her, then let him do so." (Abu Dawood, al-Nikaah, 2082; classed as hasan by al-Albaani in Saheeh Abi Dawood, 1832).

But in Islamic sharee'ah there are no specific practices that must be followed with regard to engagement. What some Muslims do, announcing the engagement, having a party to celebrate and exchanging gifts, all comes under the heading of customs which are permissible in principle, and none of them are haraam except those which sharee'ah indicates are haraam – which includes the exchange of rings between the engaged couple, a custom which is known in Arabic as "dublah." This custom goes against sharee'ah for the following reasons:

1 – Some people think that these rings increase the love between the spouses and have an effect on their relationship. This is an ignorant (jaahili) belief and is an attachment to something for which there is no basis in sharee'ah and which does not make sense.

2 – This custom involves imitating the non-Muslims such as Christians and others. It is not a Muslim custom at all. The Messenger (Peace And Blessings Of Allaah Be Upon Him) warned us against that when he said, "You will inevitably follow the paths of those who came before you, handspan by handspan, cubit by cubit, until even if they entered the hole of a lizard, you will follow them." We said, "O Messenger of Allaah, (do you mean) the Jews and Christians?" He said, "Who else?" (Narrated by al-Bukhaari, al-I'tisaam bi'l-Kitaab wa'l-Sunnah, 6889; Muslim, al-'Ilm, 6723).

And the Prophet (Peace And Blessings Of Allaah Be Upon Him) said: "Whoever imitates a people is one of them." (Narrated by Abu Dawood, al-Libaas, 4031; classed as saheeh by al-Albaani in Saheeh Abi Dawood, 3401).

3 – This engagement usually takes place before the 'aqd (marriage contract), in which case it is not permissible for the man to put the ring on his fiancée's hand himself, because she is still a stranger (non-mahram) to him, and has not yet become his wife.

Finally, we will quote the words of Shaykh Ibn 'Uthaymeen (may Allaah have mercy on him) on this matter:

" 'Dublah' is a word that refers to the engagement ring. In principle there is nothing wrong with rings (i.e., they are permissible), unless they are accompanied by certain beliefs, as some people do when the man writes his name on the ring that he gives to his fiancée, and the woman writes her name on the ring that she gives to her fiancé, believing that this will guarantee the bonds between the spouses. In this case this 'dublah' or engagement ring is haraam, because it represents an attachment to something for which there is no basis in sharee'ah and which does not make sense. Similarly it is not permissible for the man to put the ring on the woman's hand himself, because she is not yet his wife, so she is still a stranger (i.e., non-mahram) to him; she is not his wife until after the marriage contract is done."

Al-Fataawa al-Jaami'ah li'l-Mar'ah al-Muslimah, 3/914.