Question: What is the view of the religion concerning [pre-marital] relations?

Response: If the questioner means by "before marriage," before consummation of the marriage but after the contract¹, the there is no harm in such relations since she is his wife by virtue of the contract, even though they have not decorously consummate the marriage. However, if it is before the marriage, such as during the period of engagement or otherwise, such contact is forbidden and impermissible. It is not allowed for a man to enjoy a nor related woman's company, either by speech, look or private company. It is confirmed that the Prophet (peace be upon him) said,

"A man cannot be alone with a woman except in the presence of [one of her] mahram. And a woman cannot travel except with a mahram."²

In sum, if that contact or association is after the marriage contract, there is no harm in it. If it is before the marriage ceremony, even if it is after proposal and acceptance, it is not allowed. Such behavior is forbidden for him since the woman is a non-relative and non-wife until they conclude the marriage contract.

Shaikh ibn Uthaimin

______________________

Footnote

1. Here the Shaikh is referring to a practice which is quite common in the Muslim world. Sometimes, the marriage contract is performed but the two will not live together as husband and wife for some time. However, as soon as the marriage contract is done, the two are husband and wife and are legally free to behave as such toward one another (although "custom" may say otherwise). This is not to be confused with the period of engagement. During engagement, the two have agreed that they will get married but they yet to actually perform the marriage contract and become truly husband and wife.--JZ

2. Recorded by Muslim. Al-Bukhari has something similar.--JZ

Islamic Fatawa Regarding Women - Darussalam Pg.195-196