To invoke for increase of offspring, along with His Blessings. Sahih al-Bukhari 6380, 6381
Arabic hadith text
حَدَّثَنَا أَبُو زَيْدٍ، سَعِيدُ بْنُ الرَّبِيعِ حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، قَالَ سَمِعْتُ أَنَسًا ـ رضى الله عنه ـ قَالَ قَالَتْ أُمُّ سُلَيْمٍ أَنَسٌ خَادِمُكَ. قَالَ "اللَّهُمَّ أَكْثِرْ مَالَهُ وَوَلَدَهُ، وَبَارِكْ لَهُ فِيمَا أَعْطَيْتَهُ "
Translation
Narrated Anas
Um Sulaim said (to the Prophet), "Anas is your servant; so please invoke for Allah's blessings for him." He said "O Allah! Increase his wealth and offspring, and Bless (for him) whatever You give him."