Sunan Ibn Majah Book 5, Hadith 142
“They sent me to Zaid bin Khalid to ask him
about
passing in front of one who is performing prayer. He told me
that the
Prophet (ﷺ) said: ‘Waiting for forty is better than passing
in
front of one who is performing prayer.’”
(One of the narrators) Sufyan said: "I do not know if he meant forty years, months, days, or hours."
“When anyone of you performs prayer, let him put something in front of him. If he cannot find anything then let him put a stick. If he cannot find one, then let him draw a line. Then it will not matter if anything passes in front of him.”
“What did you hear from the Prophet (ﷺ) about a man when he is performing prayer?” He said: “I heard the Prophet (ﷺ) saying: ‘If anyone of you knew (how great is the sin involved) when he passed in front of his brother who is performing prayer, then waiting for forty’,”
(one of the narrators) said: “I do not know if he meant forty years, forty months, or forty days, ‘would be better for him than that.”