If Allaah has promised for sustained sustenance and prohibited abortion, then why does sustenance (money in particular) keep on diminishing with each child added to the family? Why do resources not increase with each added member of the family? Rather, it keeps on becoming difficult to pay for day-to-day bare minimums (without any greed for luxuries). A cycle squeezing the bare minimums is repeated every now and then. Is thinking like this bad for one's faith? How can one satisfy his inner self?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

Thinking in the same manner that you mentioned contradicts complete Eemaan (faith). A Muslim must believe in the contents of the Islamic texts and the fact that Allah guaranteed the sustenance of His Creation.

Shaykh Ibn Baaz was asked in Fataawa Noorun ‘alaa Ad-Darb about this verse and the famine in Africa, and he answered:

“The verse means its literal meaning; the disasters and famine that Allah predestines do not harm except those whose appointed time for death has come and whose provision is finished, but those who are predestined to live longer or those whose provision is not finished, then Allah brings their sustenance in many ways; they might know it, and they might not know it, because Allah says (what means): {And whoever fears Allah - He will make for him a way out. And will provide for him from where he does not expect.} [Quran 65:2-3] Allah also says (what means): {And how many a creature carries not its [own] provision. Allah provides for it and for you. And He is the Hearing, the Knowing.} [Quran 29:60] Moreover, the Prophet said, No soul will die until it has completed its appointed term and received its provision in full.' Nonetheless, a person may be punished by poverty and deprivation of sustenance because of some things that he did, such as laziness or not undertaking the means that he is able to undertake, or due to him committing sins that Allah forbade him from committing. Allah says (what means): {What comes to you of good is from Allah, but what comes to you of evil, [O man], is from yourself.} [Quran 4:79] Allah also says (what means): {And whatever strikes you of disaster - it is for what your hands have earned; but He pardons much.} [Quran 42:30] It has also been confirmed that the Prophet said, 'A man is deprived of provision because of the sins that he commits.' [Ahmad, an-Nasaa’i, and Ibn Maajah]

It may be also that a person is afflicted by poverty, disease and other misfortunes in order to test his gratefulness and patience, as Allah says (what means): {And We will surely test you with something of fear and hunger and a loss of wealth and lives and fruits, but give good tidings to the patient. Who, when disaster strikes them, say: Indeed we belong to Allah, and indeed to Him we will return.} [Quran 2:155-156] Allah further says (what means): {And We tested them with good [times] and bad that perhaps they would return [to obedience].} [Quran 7:168]

What is meant in this verse by {good} is the blessings, and what is meant by {bad} is the misfortunes. The Prophet said, 'Strange indeed is the matter of a believer; there is good in all his affairs, and this is only for the believer. If something good happens to him and he is grateful, then this is good for him, and if a calamity befalls him and he is patient, then this is also good for him.' [Muslim]

There are many verses and ahaadeeth in this regard." [End of quote]

For more benefit, please refer to fatwa 322558.

Indeed, happiness is not in having a large amount of money, but it is in being content with what Allah has given a person. Al-Khaadimi said in Bareeqah Mahmoodiyyah:

 “Richness means not needing others, so if a person is pleased with what Allah has given him and he did not ask for more, then he would be far from needing the people because richness is not with abundance of supply; rather, richness is self-content, and contentment is honor by Allah, and its opposite is poverty and humiliation (in relation) to others, and a person who is not contended will never be satiated. Contentment is honor, richness and freedom, whereas lacking contentment is humiliation and enslavement (to people).”

He said this statement while commenting on the hadeeth of the Prophet in which he said, "Be pleased with what Allah has predestined for you and you will be the richest of people.” [Ahmad and at-Tirmithi]

Allah knows best.