Titus 3:3

For we ourselves also were sometimes foolish
Nothing has a greater tendency to promote humility, and check pride in the saints, than to reflect upon their past state and condition, what they themselves once were; and this is a reason why magistrates, though evil men, should be obeyed in things good and lawful, and why no man should be spoken evil of, and why every man should be treated in a gentle manner, and used with mildness and meekness; since the apostle himself, and Titus, and other saints, whom he designed this as an instruction for, were formerly, in their unregenerate state, just such persons themselves; and therefore should not glory over them, and treat them in a contemptuous manner: and besides, the same grace that had made a difference in them, could make one in these also, and which might be made in God's own time: and particularly, whereas they observed great ignorance in these men, they should consider that they also had been "foolish", and without understanding of things, divine and spiritual, and neither knew their own state and condition, nor the way of salvation by Christ; yea, the apostle himself, though he had a zeal for God, yet not according to knowledge; he did not know lust, nor the exceeding sinfulness of sin, until he was enlightened by the Spirit of God; he was ignorant of the righteousness of God, and went about to establish his own, which he imagined to be blameless; and thought he ought to do many things contrary to the name of Jesus:

disobedient;
both to the law of God, and Gospel of Christ; disbelieving the truths of the Gospel, and not subjected to the ordinances of it, notwithstanding the evidence with which they came, and the miracles by which they were confirmed.

Deceived;
by the old serpent Satan, who deceives the whole world; and by an evil heart of unbelief, as well as by false teachers and leaders; and so, as the word signifies, were wandering about in darkness and ignorance, and were as sheep going astray, until they were returned unto the Shepherd and Bishop of souls.

Serving divers lusts and pleasures;
the lusts of the flesh are many and various, which promise pleasure to them that obey them, though that is but imaginary, and very short lived, and which subjects persons to bondage and slavery; for such who indulge to these things, are overcome by them, led captive, and brought into bondage, and are the servants of sin, vassals and slaves to their own corruptions; and such these saints had been, here spoken of:

living in malice and envy;
they had not only malice and envy in their hearts against their fellow creatures, but practised it in their lives; yea, their lives were a continued series of malice and envy; particularly this was true of the apostle, who haled men and women out of their houses, and committed them to prison; breathed out slaughter and threatenings against the saints; was exceedingly mad against them, persecuted them to strange cities, and compelled them to blaspheme, and gave his vote for punishing them with death.

Hateful, and hating one another;
abominable in the sight of God, as considered in themselves, and on account of their nature and practices; and to be abhorred by all good men; and who, by their continual feuds, quarrels, and animosities among themselves, showed an hatred, an abhorrence of one another.