Yes. It was necessary that angels should be deputed for the guardianship of men, in order to regulate them and move them to good, because as regards things to be done human cognition and affection can vary and fail from good in many ways.
Necessarium fuit quod hominibus Angeli ad custodiam deputarentur, per quos regularentur et moverentur ad bonum, quia in rebus agendis cognitio et affectus hominis multipliciter variari et deficere possunt a bono.
Two things are required for a good action; first, that the affection be inclined to good, which is effected in us by the habit of moral virtue. Secondly, that reason should discover the proper ways to make perfect the good of virtue; this the Philosopher (Ethic. vi) attributes to prudence.
Ad bene operandum duo requiruntur. Primo quidem, quod affectus inclinetur ad bonum, quod quidem fit in nobis per habitum virtutis moralis. Secundo autem, quod ratio inveniat congruas vias ad perficiendum bonum virtutis, quod quidem philosophus attribuit prudentiae.
As regards the first, God guards man immediately by infusing into him grace and virtues; as regards the second, God guards man as his universal instructor, Whose precepts reach man by the medium of the angels, as above stated (Q111, A1).
Quantum ergo ad primum, Deus immediate custodit hominem, infundendo ei gratiam et virtutes. Quantum autem ad secundum, Deus custodit hominem sicut universalis instructor, cuius instructio ad hominem provenit mediantibus Angelis, ut supra habitum est.
As men depart from the natural instinct of good by reason of a sinful passion, so also do they depart from the instigation of the good angels, which takes place invisibly when they enlighten man that he may do what is right. Hence that men perish is not to be imputed to the negligence of the angels but to the malice of men. That they sometimes appear to men visibly outside the ordinary course of nature comes from a special grace of God, as likewise that miracles occur outside the order of nature.
Sicut homines a naturali instinctu boni discedunt propter passionem peccati; ita etiam discedunt ab instigatione bonorum Angelorum, quae fit invisibiliter per hoc quod homines illuminant ad bene agendum. Unde quod homines pereunt, non est imputandum negligentiae Angelorum, sed malitiae hominum. Quod autem aliquando, praeter legem communem, hominibus visibiliter apparent, ex speciali Dei gratia est, sicut etiam quod praeter ordinem naturae miracula fiunt.
By free-will man can avoid evil to a certain degree, but not in any sufficient degree; forasmuch as he is weak in affection towards good on account of the manifold passions of the soul. Likewise universal natural cognition of the law, which by nature belongs to man, to a certain degree directs man to good, but not in a sufficient degree; because in the application of the universal principles of law to particular actions man happens to be deficient in many ways. Hence it is written (Wisdom 9:14): "The thoughts of mortal men are fearful, and our counsels uncertain." Thus man needs to be guarded by the angels.
Per liberum arbitrium potest homo aliqualiter malum vitare, sed non sufficienter, quia infirmatur circa affectum boni, propter multiplices animae passiones. Similiter etiam universalis cognitio naturalis legis, quae homini naturaliter adest, aliqualiter dirigit hominem ad bonum, sed non sufficienter, quia in applicando universalia principia iuris ad particularia opera, contingit hominem multipliciter deficere. Unde dicitur Sap. IX, "cogitationes mortalium timidae, et incertae providentiae nostrae." Et ideo necessaria fuit homini custodia Angelorum.