﴿ ۞ فَلَمَّآ أَحَسَّ عِيسَىٰ مِنْهُمُ ٱلْكُفْرَ قَالَ مَنْ أَنصَارِىٓ إِلَى ٱللَّهِ ۖ قَالَ ٱلْحَوَارِيُّونَ نَحْنُ أَنصَارُ ٱللَّهِ ءَامَنَّا بِٱللَّهِ وَٱشْهَدْ بِأَنَّا مُسْلِمُونَ ﴾

“And when Jesus became aware of their refusal to acknowledge the truth, he asked: "Who will be my helpers in God's cause?" The white-garbed ones replied: "We shall be [thy] helpers [in the cause] of God! We believe in God: and bear thou witness that we have surrendered ourselves unto Him!”

Please check ayah 3:54 for complete tafsir.