۞ وَالْوَالِدٰتُ يُرْضِعْنَ اَوْلَادَهُنَّ حَوْلَيْنِ كَامِلَيْنِ لِمَنْ اَرَادَ اَنْ يُّتِمَّ الرَّضَاعَةَ ۗ وَعَلَى الْمَوْلُوْدِ لَهٗ رِزْقُهُنَّ وَكِسْوَتُهُنَّ بِالْمَعْرُوْفِۗ لَا تُكَلَّفُ نَفْسٌ اِلَّا وُسْعَهَا ۚ لَا تُضَاۤرَّ وَالِدَةٌ ۢبِوَلَدِهَا وَلَا مَوْلُوْدٌ لَّهٗ بِوَلَدِهٖ وَعَلَى الْوَارِثِ مِثْلُ ذٰلِكَ ۚ فَاِنْ اَرَادَا فِصَالًا عَنْ تَرَاضٍ مِّنْهُمَا وَتَشَاوُرٍ فَلَا جُنَاحَ عَلَيْهِمَا ۗوَاِنْ اَرَدْتُّمْ اَنْ تَسْتَرْضِعُوْٓا اَوْلَادَكُمْ فَلَا جُنَاحَ عَلَيْكُمْ اِذَا سَلَّمْتُمْ مَّآ اٰتَيْتُمْ بِالْمَعْرُوْفِۗ وَاتَّقُوا اللّٰهَ وَاعْلَمُوْٓا اَنَّ اللّٰهَ بِمَا تَعْمَلُوْنَ بَصِيْرٌ ( البقرة: ٢٣٣ )
Walwaa lidaatu yurdi'na awlaada hunna hawlaini kaamilaini liman araada ai yutimmar radaa'ah; wa 'alalmawloodi lahoo rizuhunna wa kiswatuhunna bilma'roof; laatukallafu nafsun illaa wus'ahaa; laa tudaaarra waalidatum biwaladihaa wa laa mawloodul lahoo biwaladih; wa 'alal waarisi mislu zaalik; fa in araadaa Fisaalan 'an taraadim minhumaa wa tashaawurin falaa junaaha 'alaimaa; wa in arattum an tastardi'ooo awlaadakum falaa junaaha 'alaikum izaa sallamtum maaa aataitum bilma'roof; wattaqul laaha wa'lamooo annal laaha bimaa ta'maloona baseer (al-Baq̈arah 2:233)
Mothers may nurse [i.e., breastfeed] their children two complete years for whoever wishes to complete the nursing [period]. Upon the father is their [i.e., the mothers'] provision and their clothing according to what is acceptable. No person is charged with more than his capacity. No mother should be harmed through her child, and no father through his child. And upon the [father's] heir is [a duty] like that [of the father]. And if they both desire weaning through mutual consent from both of them and consultation, there is no blame upon either of them. And if you wish to have your children nursed by a substitute, there is no blame upon you as long as you give payment according to what is acceptable. And fear Allah and know that Allah is Seeing of what you do. (Al-Baqarah  : 233)
1 Mufti Taqi Usmani
Mothers (should) suckle their children for two full years, for one who wants to complete the (period of) suckling. It is the obligation of the one to whom the child belongs that he provides food and clothing for them (the mothers) with fairness. Nobody is obligated beyond his capacity. No mother shall be made to suffer on account of her child, nor the man to whom the child belongs, on account of his child. Likewise responsibility (of suckling) lies on the (one who may become an) heir (of the child). Now, if they want to wean, with mutual consent and consultation, there is no sin on them. And If you want to get your children suckled (by a wet-nurse), there is no sin on you when you pay off what you are to give with fairness, and fear Allah, and be assured that Allah is watchful of what you do.