It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that I came riding on a donkey and I was near the age of puberty, and the Messenger of Allah (peace and blessings be upon him) was leading the prayer at Mina. I passed in front of a part of the row, then I dismounted and left the donkey, it kept grazing, and I joined the row. After the prayer, no one found anything objectionable in this.

Imam Malik (may Allah have mercy on him) was informed that Sayyiduna Sa’d bin Abi Waqqas (may Allah be pleased with him) used to pass in front of the rows during prayer.
Imam Malik (may Allah have mercy on him) said: I consider this act permissible in the situation when the prayer has started, the imam has said the opening takbeer, and a person cannot find a place to enter except by passing in front of the rows.

Imam Malik (may Allah have mercy on him) received from Sayyiduna Ali (may Allah be pleased with him), he used to say: If anything passes in front of a person praying, his prayer is not invalidated.

It is narrated from Hazrat Salim bin Abdullah that Sayyiduna Abdullah bin Umar (may Allah be pleased with them) used to say that if anything passes in front of a person offering prayer, his prayer is not invalidated.