Messenger of Allah (S) said: "Whoever prays six Rak'ah after Al-Maghrib, and he does not speak about anything between them, then they will be counted for him as twelve years of worship."  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ صَلَّى بَعْدَ الْمَغْرِبِ سِتَّ رَكَعَاتٍ لَمْ يَتَكَلَّمْ فِيمَا بَيْنَهُنَّ بِسُوءٍ عُدِلْنَ لَهُ بِعِبَادَةِ ثِنْتَىْ عَشْرَةَ سَنَةً