Sahih Muslim 8453
In-book no 1176وَحَدَّثَنَاهُ عَبْدُ اللَّهِ بْنُ عَبْدِ الرَّحْمَنِ الدَّارِمِيُّ، أَخْبَرَنَا يَحْيَى بْنُ حَسَّانَ، حَدَّثَنَا وُهَيْبُ بْنُ خَالِدٍ، حَدَّثَنَا مَنْصُورٌ، بِهَذَا الإِسْنَادِ وَقَالَ مَنْصُورٌ " فَلْيَنْظُرْ أَحْرَى ذَلِكَ لِلصَّوَابِ " .
This hadith is reported by Mansur with the same chain of transmitters, but with these words: " He should aim at correct (prayer) and it is advisable."