Some of the people may fear having babies out their ignorance; while the Islamic teachings and traditions tell us not to fear raising children because Allah (SWT) would sustain them.
These days, most of us might fear having babies just because of financial problems. But reading and obeying the following hadiths and instructions would help us to raise more children. "Bakr ibn Salih" narrates that: ‘I wrote to Abu Al-Hassan (A), ‘I kept aside from seeking the children since five years ago, and that is because my wife disliked that, and she said, ‘It is difficult upon me, their upbringing, due to the scarcity of the things. So what is your view’? So he (A) wrote to me: ‘Seek the children, for Allah (SWT) Mighty and Majesty would Sustain them’. (Wasail al-Shia, v.21, p.360) [1]
In addition, Allah, the Almighty, has promised in the holy Qur'an: "We provide for them [your children] and for you" (Al-Isra/31)
[1] عَنْ بَكْرِ بْنِ صَالِحٍ قَالَ: كَتَبْتُ إِلَى أَبِي الْحَسَنِ ع أَنِّي اجْتَنَبْتُ طَلَبَ الْوَلَدِ مُنْذُ خَمْسِ سِنِينَ وَ ذَلِكَ أَنَّ أَهْلِي كَرِهَتْ ذَلِكَ وَ قَالَتْ إِنَّهُ يَشْتَدُّ عَلَيَّ تَرْبِيَتُهُمْ لِقِلَّةِ الشَّيْءِ فَمَا تَرَى فَكَتَبَ ع إِلَيَّ اطْلُبِ الْوَلَدَ فَإِنَّ اللَّهَ عَزَّ وَ جَلَّ يَرْزُقُهُم .