Al-Kāfi - Volume 6 > One Who is not Lawful for her Husband without Marriage to another Man
Hadith #6

عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ عَلِيِّ بْنِ أَسْبَاطٍ عَنْ عَلِيِّ بْنِ الْفَضْلِ الْوَاسِطِيِّ قَالَ كَتَبْتُ إِلَى الرِّضَا ( عليه السلام ) رَجُلٌ طَلَّقَ امْرَأَتَهُ الطَّلَاقَ الَّذِي لَا تَحِلُّ لَهُ حَتَّى تَنْكِحَ زَوْجاً غَيْرَهُ فَتَزَوَّجَهَا غُلَامٌ لَمْ يَحْتَلِمْ قَالَ لَا حَتَّى يَبْلُغَ فَكَتَبْتُ إِلَيْهِ مَا حَدُّ الْبُلُوغِ فَقَالَ مَا أَوْجَبَ عَلَى الْمُؤْمِنِينَ الْحُدُودَ .

6. A number of our people have narrated from Sahl ibn Ziyad from Ali ibn Asbat from Ali ibn al-Fadl al-Wasitiy who has said the following: “I once wrote to al-Rida’, ‘Alayhi al-Salam, and asked, ’A man has divorced his wife as such that she cannot become lawful for him in marriage without marriage with another man; but a boy who is not mature married her. He (the Imam) replied, ‘No, until he becomes mature.’ I then wrote and asked, ‘What is the limit of maturity?’ He (the Imam) replied, ‘It is that which makes it obligatory for believers to execute penalties.’”