From the affirmation of Allah's absolute purity and the refutation of assumed Godhood of Sayyidna 'Isa (علیہ السلام) earlier, the text now moves to further strengthen the argument by showing that Sayyidna 'Isa (علیہ السلام) would himself confess to being a servant of Allah and so will the angels (which includes Sayyidna Jibra'il (علیہ السلام) alleged to be a person of Trinity). Then, follows the warning for those who choose to retract in distaste and the good news for those who believe and are good in deeds for they will be rewarded for their belief and deeds with many more added graces from Allah.
Commentary
The Honour of being a servant of Allah
Maulana Shabbir Ahmad ` Usmani, in his comments on the opening statement of Verse 172: لَّن يَسْتَنكِفَ الْمَسِيحُ أَن يَكُونَ عَبْدًا لِّلَّـهِ (The Masih shall never spurn being a slave of Allah, nor shall the angels, the close ones), says that so it is because being a servant of Allah, being devoted to His worship and being obedient to His will and command, is an honour by itself and certainly a nobility of the highest class. Sayyidna Masih (علیہ السلام) and the close angels are the best testifiers to the worth and value of this blessing. How could they spurn an honour like that? Quite contrary to this, the worst disgrace and dishonour there can be imagined lies in worshipping someone other than Allah. This is what the Christians did when they took Sayyidna Masih (علیہ السلام) as the son of Allah and the object of their worship. Similar was the case with disbelievers who took angels as daughters of Allah and started worshipping them alongwith their idols. So, for them, there is punishment, and disgrace. (Notes in Tafsir Usmani)