Allah said,

[فَإِنْ أَرْضَعْنَ لَكُمْ]

(Then if they suckle them for you,) meaning, when pregnant women give birth and they are irrevocably divorced by the expiration of the `Iddah, then at that time they may either suckle the child or not. But that is only after she nourishes him with the milk, that is the early on milk which the infant's well-being depends upon. Then, if she suckles, she has the right to compensation for it. She is allowed to enter into a contract with the father or his representative in return for whatever payment they agree to. This is why Allah the Exalted said,

[فَإِنْ أَرْضَعْنَ لَكُمْ فَـَاتُوهُنَّ أُجُورَهُنَّ]

(Then if they suckle the children for you, give them their due payment,) Allah said,

[وَأْتَمِرُواْ بَيْنَكُمْ بِمَعْرُوفٍ]

(and let each of you deal with each other in a mannerly way.) meaning, the affairs of the divorced couple should be managed in a just way without causing harm to either one of them, just as Allah the Exalted said in Surat Al-Baqarah,

[لاَ تُضَآرَّ وَلِدَةٌ بِوَلَدِهَا وَلاَ مَوْلُودٌ لَّهُ بِوَلَدِهِ]

(No mother shall be treated unfairly on account of her child, nor father on account of child.) (2:233) Allah said,

[وَإِن تَعَاسَرْتُمْ فَسَتُرْضِعُ لَهُ أُخْرَى]

(But if you make difficulties for one another, then some other woman may suckle for him.) meaning, if the divorced couple disagrees, because the woman asks for an unreasonable fee for suckling their child, and the father refuses to pay the amount or offers an unreasonable amount, he may find another woman to suckle his child. If the mother agrees to accept the amount that was to be paid to the woman who agreed to suckle the child, then she has more right to suckle her own child. Allah's statement,

[لِيُنفِقْ ذُو سَعَةٍ مِّن سَعَتِهِ]

(Let the rich man spend according to his means;) means, the wealthy father or his representative should spend on the child according to his means,

[وَمَن قُدِرَ عَلَيْهِ رِزْقُهُ فَلْيُنفِقْ مِمَّآ ءَاتَاهُ اللَّهُ لاَ يُكَلِّفُ اللَّهُ نَفْساً إِلاَّ مَآ ءَاتَاهَا]

(and the man whose resources are restricted, let him spend according to what Allah has given him. Allah puts no burden on any person beyond what He has given him.) This is as Allah said,

[لاَ يُكَلِّفُ اللَّهُ نَفْسًا إِلاَّ وُسْعَهَا]

(Allah does not burden a person beyond what He can bear.) [2:286]