Its better to ask these questions from a learned scholar brother rather than on a forum is my sincere advice. Halal slaughter is mentioned in quran and hadith. Quran says:
"Forbidden for you are carrion, and blood, and flesh of swine, and that which has been slaughtered while proclaiming the name of any other than God, and one killed by strangling, and one killed with blunt weapons, and one which died by falling, and that which was gored by the horns of some animal, and one eaten by a wild beast, except those whom you slaughter; and that which is slaughtered at the altar and that which is distributed by the throwing of arrows [for an omen]; this is an act of sin.
— al-Māʼidah 5:3
Sayyiduna S'ad (radhiallahu anhu) relates that the Prophet (salallahu alaihi was sallam) said “O S'ad purify your food (and as a result) you will become one whose supplications are accepted. I swear by Him in whose hands the soul of Muhammad lies, verily a servant (of Allah) tosses a Haram (impermissible) food morsel in his stomach (due to which) no good deed is accepted from him for 40 days” (Tabrani 6395)
Sayyiduna Abu Hurayrah (radhiallahu anhu) narrates that the Prophet (salallahu alaihi wasallam) said: “Allah the Almighty is pure and accepts only that which is pure. Allah (swt) has commanded the faithful to do that which he commanded the Messengers, and the Almighty has said: “O Messengers! Eat of the pure things and do right”. And Allah the Almighty has said: “O you who believe! Eat of the pure things We have provided you.”, then Rasulullah (salallahu alaihi wasallam) mentioned (the case of) a man traveling on a long ardous journey, greatly troubled and distressed, with disheveled hair crying to Allah swt, O my Lord! O my Lord! But, his food is Haram, his drink is Haram, his dress is Haram and he is nourished with Haram. How then his du’a be accepted (Muslim 1015)