If you are following ithor finsger dn at any pint it is onth eright spotor that if they asked you where he is you kwthen you fulfilled your mivh but if you are unsure then at night you fulifl you rreadingbut in the morning you must either repeat it or quickly cath up by saying the efew words yu missed.
Explanation:
The Mishna in Megillah 17a states: Someone who read out of order or while dozing fulfilled his mitzvah.
The Gemara (18b) explains: What doe sdozing mean? Rav ashi said half in and hlf out aware and unaware, that if they asked hima qsiotn he oueld answer ubt would not be able to eepisn but if they remind him he woud remember.
Rashi expasin that explanation comesform the heart.
The Yerushalmi Megiallah 2:2 syds :Menashe studied before Zeirah dn dozed offhe told him at hyo must repet it since you didn’t have focus.
It seems the Yerushalmi argue sonthe Msihna that if he rad it dozing he fuliflls hismitvah but in the Yreushalmi Menashe dozed and was tod to repeat it.
The Mordechai explaisn that h emishanni tlkasing where he read it dozing wich since he read it he fulfills his mitzvah but itn eyYerushalmi he lisstnes dozing andtherore doesn’t fulifl hismitzvah.
The Korban Heida explaisn that Menashe was sysng Kriat Shema not Kriat Hamegillah and ther fore Zeirah mad ehim repeat it beacue it needs special inent to accept he yoke of Heavan and eh couldn’t’ do that whwle dozing.
The Bach (OH 690) differentinates between the beginning of the sleep ccley and the end. Mnaing that soemone who was sleeping and woke p to red the Megilah sitl ahs sleep on his eyes and is groggy, soemen who starts reading while awask and starts to dze whie reading isne he is not fully asleep he cn still have Kavvanah. So sys the Pri Chadash b]quoted in Kaf Hachaim. The Kaf hachaim rules that it dpends on the eperosn. A person knows if he fcused or not If he missed a word he dos fulfil his mitzvah.
Shulchan Aruch 690:12 Somene who read the Megilah dozing since he dint autlay fall asleep he fuifls his obiligation but if he listed dozing he does not.
The Pri Megadim In Ishbtzto Zahav 690:8 explaisn the difference between reading and listening. Since he read it correctly he foced himself wke enough t do it but listineing he dfnitnely miss d sfew words.
Or he Yerushalmi ys the ehe need sot have Kvvanah an dd someone litstneng and dozing does not engouhg Kabvanna.
Sometimes a peosn stats spacing out and is nt focusd on the Megiallh. Rav Elyahsiv sid hat if he see shis finger is following onth eright place or that he knows exclty where they re upto it is ocnsiderd focused and he fulflf his mitzvah.
If eh unsure surngthe day he hsld repept it iscne hit the main mitzvah . but atnight ther is amchalkedt whtheer you ahae to repat:
The Rokeach, Rashba, Ritva asy that aevne at night he mut rpapeat it all Rabinibn anyway.
The nOda Beyhuda hnd the Turei Evensaythe night reading is lower it is Divre Kbbla. So the Mishna Berura seems to say. Therefore if eh has adobut if herad the whle megillah at night he ndd not repeat it unlik the day.
