While we were sitting in the company of 'Abdullah bin 'Umar there came in his steward. He (Ibn 'Umar) said: Have you supplied the provision to the slaves? He said: No. Upon this he said: Go and give (the provision) to them, for the Messenger of Allah (sallallaahu alayhi wa sallam) has said: This sin is enough for a man that he withholds the subsistence from the one whose Quut [food, nourshiment] he owns.
[Sahih Muslim 996]
This incudes your children, wife, khaadim, and others.
Khaalid bin Uthmaan al-Sabt says regarding the phrase:
"This sin is enough for a man…"
لو لم يكن له من الإثم إلا هذا لكان ذلك كافياً لعظمه
Had he not had any sin except for this one [sin] it would have been sufficient given its magnitude.
Do not be miserly and earn yourself a major sin.