Daily Hadith Thu 28-Jul-2011 - 27 Shaban 1432 حديث اليوم
باب فضل الذكر والحثِّ عليه
وعن أبي هريرةَ رضي اللَّه عَنْهُ أنَّ رسُولَ اللَّه صَلّى اللهُ عَلَيْهِ وسَلَّم قال : « أقربُ ما يَكونُ العبْدُ مِن ربِّهِ وَهَو ساجدٌ ، فَأَكثِرُوا الدُّعاءَ » رواهُ مسلم .
1428/244 - رياض الصالحين
The Excellence of the Remembrance of Allah
Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (PBUH) said, "A slave becomes nearest to his Rubb when he is in prostration. So increase supplications while prostrating."[Muslim].


Commentary:
Both the Ahadith mentioned above, evidently show that there is greater possibility of acceptance of an invocation which is made in prostration. Therefore, one must do it in the voulntary Salat.
244/1428 - Riyad Us-Saliheen (Gardens of the Righteous)
Thu 28-Jul-2011 - 27 Shaban 1432