Dating

The Noble Qur'an - Al-Ma'idah 5:5

...(Lawful to you in marriage) are chaste women from the believers and chaste women from those who were given the Scripture (Jews and Christians) before your time, when you have given their due Mahr (bridal-money given by the husband to his wife at the time of marriage), desiring chastity (i.e. taking them in legal wedlock) not committing illegal sexual intercourse, nor taking them as girlfriends. ...

"Shacking up" brings a curse taken to the grave

Hadith - Sahih Muslim, Narrated AbudDarda'

AbudDarda' related from the Prophet of Allah that he came upon a (slave) woman who was in the advanced stage of pregnancy at the door of a tent. He said: Perhaps he (the man accompanying her) intends to cohabit with her. They said: Yes. Thereupon Allah's Messenger said: I had decided to curse him with such a curse as may go along with him to his grave. How can he own him (the child to be born) and that is not lawful for him, and how can be take him as a servant for that is not lawful for him?

Sex outside of marriage is prohibited

Hadith - Sahih Bukhari Volume 3, Book 48, Number 817, Narrated Zaid bin Khalid

Allah's Apostle ordered that an unmarried man who committed illegal sexual intercourse be scourged one hundred lashes and sent into exile for one year.

A Muslim cannot date and should always have the intentions not be alone with a non-mahram; if it is your intentions not to be alone with a non-mahram, but circumstances beyond your control mandate that you are (such as entering a store, placing an order, calling a plumber to fix an emergency leak), that is different.  It must be your intentions not to be alone with a non-mahrahm person, though.

Islam protects us from ourselves by segregating men from women who are not directly related (these people are known as mahrham) as specific in the Qur'an.  Instead of dating, a Muslim and Muslimah meet in a pre-arranged place (such as a room in the Masjid) with a wali/witness/guardian/escort present in the room.  The couple will discuss a marriage contract and ask questions of importance to them regarding marriage.  The best person to seek for a spouse is the pious.     

Being alone with a non-mahram

Hadith - Ahmad and Al-Tirmidhi 3118, Narrated Umar ibn al-Khattab , Tirmidhi transmitted it.

The Prophet said, "Whenever a man is alone with a woman the Devil makes a third."

Hadith - Sahih Bukhari, Book 25, Number 5403, Narrated Abdullah ibn Amr ibn al-'As

Some persons from Banu Hisham entered the house of Asma' daughter of Umays when AbuBakr also entered (and she was at that time his wife). He (AbuBakr) saw it and disapproved of it and he made a mention of that to Allah's Messenger and said: I did not see but good only (in my wife).

Thereupon Allah's Messenger said: Verily Allah has made her immune from all this. Then Allah's Messenger stood on the pulpit and said: After this day no man should enter the house of another person in his absence, but only when he is accompanied by one person or two persons.

Hadith - Sahih Bukhari Book 25, Number 5399, Narrated Jabir ibn Abdullah

Allah's Messenger said: Behold, no person should spend the night with a married woman, but only in case he is married to her or he is her Mahram.

Hadith - Al-Tirmidhi 3119, Narrated Jabir ibn Abdullah
The Prophet said, "Do not visit women whose husbands are away from home, for the Devil circulates in you like your blood." He was asked if this applied to him also and said, "To me also, but Allah has helped me against him so that I may be safe." [Tirmidhi transmitted it.]

Fatawa on Phone Usage

Question: What is the ruling concerning a young man who is not married speaking to a young lady who is also not married over the telephone?

Response: It is not allowed to speak with a non-related woman with any speech that stirs desires, such as in a flirtatious, coquettish or soft manner. This is not allowed whether it is over the telephone or otherwise. Allah has said,

• "Be not soft in speech, lest those in whose heart is a disease should be moved with desire" (al-Ahzab 32).

There is no harm in casual speech due to some need if it is free from any sort of evil. However, such speech must be restricted to only what is necessary.

Shaikh ibn Jibreen

Note: "what is necessary" does not include emotional desires or 'needs'.  This is referring to accomplishing things that are necessary and cannot be avoided, i.e. there is no appropriate person available to talk to in order to accomplish the needed goal or item. For instance, speaking with a doctor or mechanic, store clerk to inquire as to a price, etc., is that which is necessary.  Socializing is not considered that which is necessary, even in the workplace.

Symptom: Feeling weak?
Prescription: Lower gaze, Do your prayers

The Noble Qur'an 24:30

Tell the believing men to lower their gaze (from looking at forbidden things), and protect their private parts (from illegal sexual acts, etc.). That is purer for them. Verily, Allah is All-Aware of what they do.

Hadith - Sahih Al-Bukhari, Vol. 9, Hadith No. 409

Narrated Ibn Mas'uud r.a.: A man kissed a woman and then came to Allah's Messenger saaws and told him of that, so this Divine Inspiration was revealed to the Prophet saaws:- "And offer prayers perfectly at the two ends of the day, and in some hours of the night; [i.e. (five) compulsory prayers]. (Verily, the good deeds remove the evil deeds (small sins). That is a reminder for the mindful." (Qur'an 11:114) The man said, "Is this instruction for me only?" The Prophet saaws said, "It is for all those of my followers who encounter a similar situation."

Avoid being alone with a non-mahram except out of necessity and when unavoidable.

• Respect yourself and your body; wait until marriage for sex.  More importantly, obey your Lord; wait until marriage for sex.
• Don't do like the kaffirs, who date. Do as your Lord commands you. Trust that Allah swt knows what is best for you.