﴿ إِذْ قَالَتِ ٱمْرَأَتُ عِمْرَٰنَ رَبِّ إِنِّى نَذَرْتُ لَكَ مَا فِى بَطْنِى مُحَرَّرًۭا فَتَقَبَّلْ مِنِّىٓ ۖ إِنَّكَ أَنتَ ٱلسَّمِيعُ ٱلْعَلِيمُ ﴾

“when a woman of [the House of] `Imran prayed: "O my Sustainer! Behold, unto Thee do I vow [the child] that is in, my womb, to be devoted to Thy service. Accept it, then, from me: verily, Thou alone art all-hearing, all-knowing!"”

Please check ayah 3:36 for complete tafsir.