Praying before time الصلاة قبل الوقت

Allaah says (interpretation of the meaning): “Verily, As-Salaah (the prayer) is enjoined on the believers at fixed hours” [al-Nisa’ 4:103] Prayer offered before its time is not valid, according to the consensus of the Muslims. If a person offers a prayer before its time: if he does that deliberately, then the prayer is invalid and he is not free of sin. If that was not done deliberately, and he did it because he thought that the time for prayer had begun, then it is not a sin, and his prayer is regarded as naafil, but he has to repeat it because one of the conditions of the prayer is that it be done at the right time. Shaykh Muhammad ibn ‘Uthaymeen, in al-Sharh al-Mumti’, 2/88. details on time of prayer http://islamqa.info/en/9940 فقد قال الله تعالى : { إن الصلاة كانت على المؤمنين كتاباً موقوتا } أي موقتاً بوقت ، وقد تقدم بيان " والصلاة لا تصح قبل الوقت بإجماع المسلمين ، فإن صلى قبل الوقت : فإن كان متعمداً فصلاته باطلة ، ولا يسلم من الإثم . وإن كان غير متعمد لظنه أن الوقت قد دخل ، فليس بآثم ، وتعتبر صلاته نفلاً ، ولكن عليه الإعادة لأن من شروط الصلاة الوقت " انتهى كلام الشيخ محمد بن عثيمين رحمه الله من الشرح الممتع (2/88) .