Narrated 'Alqamah:

It was narrated from 'Alqamah and Al-Aswad that 'Abdullah said: "The Messenger of Allah said to us: 'Whoever among you can afford it, let him get married, and whoever cannot then he should fast, for it will be a restraint (wija') for him.'"
Abu Abdur-Rahman said: (The mention of) Al-Aswad in this hadith is not preserved.

أَخْبَرَنِي هَارُونُ بْنُ إِسْحَاقَ الْهَمْدَانِيُّ الْكُوفِيُّ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مُحَمَّدٍ الْمُحَارِبِيُّ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، وَالأَسْوَدِ، عَنْ عَبْدِ اللَّهِ، قَالَ قَالَ لَنَا رَسُولُ اللَّهِ ﷺ " مَنِ اسْتَطَاعَ مِنْكُمُ الْبَاءَةَ فَلْيَتَزَوَّجْ وَمَنْ لَمْ يَسْتَطِعْ فَعَلَيْهِ بِالصَّوْمِ فَإِنَّهُ لَهُ وِجَاءٌ " . قَالَ أَبُو عَبْدِ الرَّحْمَنِ الأَسْوَدُ فِي هَذَا الْحَدِيثِ لَيْسَ بِمَحْفُوظٍ .