The question in the the title is too broad IMO.It can't be answered in few lines.
However, i have covered all the questions that are in the body and also the one that you asked in comments on adultery.
Effects of Theft:
The Manu Smriti in Chapter 12 discusses what a thief becomes in his/her next life depending on the objects that he/she has stolen.Here are a few such verses:
12.61. A man who out of greed has stolen gems, pearls or coral, or any of the many other kinds of precious things, is born among the
12.62. For stealing grain (a man) becomes a rat, for stealing yellow metal a Hamsa, for stealing water a Plava, for stealing honey a
stinging insect, for stealing milk a crow, for stealing condiments a
dog, for stealing clarified butter an ichneumon;
12.63. For stealing meat a vulture, for stealing fat a cormorant, for stealing oil a winged animal (of the kind called) Tailapaka, for
stealing salt a cricket, for stealing sour milk a bird (of the kind
12.68. That man who has forcibly taken away any kind of property belonging to another, or who has eaten sacrificial food (of) which (no
portion) had been offered, inevitably becomes an animal.(Manu Smriti)
Now,if someone steals a Brahmin's gold then that's one of the 5 grave sins(Mahapatakas).Other than that robbery/theft is only a minor sin.
A thief can also atone for the theft if he/she wants by following methods like the ones given below:
Manu Smriti 11.163. The lunar penance has been declared to be the
expiation for stealing men and women, and (for wrongfully
appropriating) a field, a house, or the water of wells and cisterns
11.165. (To swallow) the five products of the cow (pankagavya) is the atonement for stealing eatables of various kinds, a vehicle, a bed, a
seat, flowers, roots, or fruit.
Effects of donating food to the poor:
In Shastras charity of food is called "Anna Danam".
From Skanda Purana:
Narada described to Arjun about ‘daan’ (charity), its two ‘hethus’
(varieties), six ‘Adhishtaans’ (Reasons), six ‘Anks’ (Parties), two
‘Parinaams’ (end results or fruits), three bhedas (classifications)
and three ‘Vinas Saadhanas’ (negative results).....The donors of
charity must have the perspective of what kind of material is required
or useful to the receiver or otherwise the purpose of charity would be
So,charity of food to the poor is excellent compared to the same when done to some well-to-do person.
Further,Anna Dana is listed as the second best charity possible:
Three ‘Bhedas’or types of Daan are classified; the best types are
charity of houses, temples, buildings, Bhumi (farms / fields), cows,
Wells, gold and ornaments and the best of course is to give away one’s
own life itself as ‘Daan’. The Secondary Variety of charity relates to
Anna (Food grains), Vastra (Clothing), ‘Vahan’ etc.
Manu Smriti,in chapter 4,gives the effects of different kinds of charities including that of food:
Manu Smriti 4.228. If he is asked, let him always give something, be
it ever so little, without grudging; for a worthy recipient will
(perhaps) be found who saves him from all (guilt).
4.229. A giver of water obtains the satisfaction (of his hunger and thirst), a giver of food imperishable happiness, a giver of sesamum
desirable offspring, a giver of a lamp a most excellent eyesight.
4.230. A giver of land obtains land, a giver of gold long life, a giver of a house most excellent mansions, a giver of silver (rupya)
exquisite beauty (rupa),
4.232. A giver of a carriage or of a bed a wife, a giver of protection supreme dominion, a giver of grain eternal bliss, a giver of the
Veda (brahman) union with Brahman;
Also,Dana should be done with shraddha(devotion and sincerity) and not to an undeserving candidate(an Apatra).Some Danas(including Anna Dana) should however be made only when asked for.
Ayaachtaani deyaani sarva daanaani yatnatah, Annam Vidyaaha
Kanyaachahyanarthibhyona deeyate// Dvaamimau purushaa loke
swargasyopari tishthatah, Anna pradaataa durbhikshe subhikshe hema
Shandalya Muni mentions that all types of charities be offered without
being asked for and with clean conscience or with no view of securing
returns; however Vidya, Kanya and Anna must not be offered without
being asked for as a rule! Indeed, there are two types of charity
givers who attam Swarga for sure: those who heartily give away Food
during Durbhiksha and also those who happily give away gold and
clothing during the days of general prosperity!
Killing a Brahmin is considered as one of the major sins.
Manu Smriti 9.235. The slayer of a Brahmana, (A twice-born man) who
drinks (the spirituous liquor called) Sura, he who steals (the gold of
a Brahmana), and he who violates a Guru’s bed, must each and all be
considered as men who committed mortal sins (mahapataka).
AFTER serving his term in hell, the destroyer of a Brahmana, is born
afflicted with white leprosy. Therefore, for the expiation of that
sin, one should perform a penitential rite, (Satatapa Smriti,Chapter 2,Verse 1)
Abortion is stated in the Parashara Smriti as a sin that has no prayaschitta methods.
What sin is incurred in killing a Brahman, abortion causes a sin twice
as great ; there is no atonement for that sin. The abandonment of such
a woman has been ordained by law.(Parashara Smriti,Chapter 4)
Adultery is mentioned as a minor offence or an Upapataka which causes loss of caste.
Manu Smriti 11.59. Slaying kine, sacrificing for those who are
unworthy to sacrifice, adultery, selling oneself, casting off
one’s teacher, mother, father, or son, giving up the (daily) study of
the Veda, and neglecting the (sacred domestic) fire are Upatakas(minor sins)
Which kind of sin makes you suffer from mental disorders?
A person, pilfering lead, is born as suffering from head-diseases.
Fasting for a day, he should give away one Dhenu weight of clarified
butter according to the proper regulations. (7)
By stealing milk curd a person is born insane. For purification, curd,
one Dhcnu in weight, should be given by him unto a Vipra. (9)(Satatapa Smriti,Chapter 4)
NOTE-Satatapa Smriti,which i have used as a reference in this answer, is among the 18 major Smritis.