Talḥah and Zubayr's conditional allegiance rejected by ʿAlī
Nahj al-Balāgha|Volume 1|Book 3|Chapter 202
٢٠٢. وَقَالَ (عليه السلام) وَقَدْ قَالَ لَهُ طَلْحَةُ وَالزُّبَيْرُ: نُبَايِعُكَ عَلَى أَنَّا شُرَكَاؤُكَ فِي هَذَا الْأَمْرِ: لَا، وَلكِنَّكُمَا شَرِيكَانِ فِي الْقُّوَّةَ وَالِاسْتِعَانَةِ، وَعَوْنَانِ عَلَى الْعَجْزِ وَالْأَوَدِ.
202. When Ṭalḥah and az-Zubayr said to him: We are prepared to swear allegiance to you on condition that we have a share with you in this matter (of caliphate), Amīr al-mu’minīn, peace be upon him, said: No, but you will have a share in strengthening (the caliphate) and in affording assistance and you will both be helping me at the time of need and hardship.