Ibn Khuzaymah

The freed slave of Sayyiduna Ibn Abbas (may Allah be pleased with them), Kuraib, narrates that Sayyiduna Abdullah bin Abbas (may Allah be pleased with them) saw Abdullah bin Harith praying while his hair was tied in a knot at the back of his head. So he stood up and untied one of his knots, leaving the other, and Abdullah bin Harith remained engaged in his prayer (i.e., he did not make any movement from the front). Then, when he completed his prayer, he came to Sayyiduna Ibn Abbas (may Allah be pleased with them) and said, "Why did you untie my hair (knot)?" He replied, "Indeed, I heard the Messenger of Allah (peace and blessings be upon him) say: 'Verily, its example is like that of a person who prays with his hands bound.'" In the narration of Yunus, it is stated: "And his head was plaited. So Sayyiduna Ibn Abbas (may Allah be pleased with them) stood behind him and untied his braid, leaving the other braid as it was. All the narrators have used the word 'aqarra' in this way. Imam Abu Bakr (may Allah have mercy on him) says that the correct word is 'qarra'."

And the comparison of the one who ties his hair in prayer to the one whose hands are bound therein. And in it is what indicates the dislike of a person praying with his hands bound if he is able to free his hands from being tied.