فَلَمَّآ أَحَسَّ عِيسَىٰ مِنْهُمُ ٱلْكُفْرَ قَالَ مَنْ أَنصَارِىٓ إِلَى ٱللَّهِ قَالَ ٱلْحَوَارِيُّونَ نَحْنُ أَنصَارُ ٱللَّهِ
Fa-lammā aḥassa ʿĪsā minhumu'l-kufra qāla man anṣārī ila'llāh, qāla'l-ḥawāriyyūna naḥnu anṣāru'llāhi āmannā bi'llāhi wa'shhad bi-annā muslimūn · Rabbanā āmannā bimā anzalta wa'ttabaʿna'r-rasūla fa'ktubnā maʿa'sh-shāhidīn · Wa makarū wa makara'llāh, wa'llāhu khayru'l-mākirīn
"When Jesus sensed disbelief in them he said: 'Who are my helpers on the way to God?' The disciples said: 'We are God's helpers; we have believed in God. Bear witness that we are those who have handed themselves over.' · 'Our Lord! We have believed in what You sent down and we have followed the messenger; write us down among those who bear witness.' · They laid a plot; and God laid His plan. God is the best of planners."
The choice of the word is worth recording: the verse does not say "he saw" or "he knew". Aḥassa — he sensed. That is, the disbelief has not yet been spoken openly.
I record this as an observation: the sentence shows that the response is given before open hostility. And the response given is not a defence but a call: man anṣārī ila'llāh.
ٱلْحَوَارِيُّون — the root ح-و-ر: the lexicographers connect the word with the senses of whiteness and of turning to something; on the origin of ḥawārī there is no firm agreement. I impose no preference in this commentary.
And the last sentence of the answer must be recorded: wa'shhad bi-annā muslimūn — "bear witness that we are those who have handed themselves over".
This is directly connected with verse 19 of the sūra and confirms what I recorded there: the word islām is here the self-naming of the community around Jesus. This is a fact of usage verifiable from the text.
The root م-ك-ر: to lay a scheme in secret. The root was treated at 27/50-51 in al-Naml and at 13/42 in al-Raʿd.
Per the method (Method) I enter a note, and it has been kept consistently in the series: when the word is used of God it does not mean deceiving or wronging. In Arabic this is called mushākala (answering with the same word): the response is named with the wording of the first act.
And the sentence itself shows this: wa'llāhu khayru'l-mākirīn — "the best of planners". The attribute "best" records within the sentence that the verb is not meant in a bad sense.
This distinction was treated at 8/30 in al-Anfāl (wa yamkurūna wa yamkuru'llāh). I rely on that treatment and do not repeat it here.