For I was alive without the law once - “In the days of my ignorance, when, in this sense, a stranger to the law, I deemed myself a righteous man, and, as such, entitled to life at the hand of God.”
but when the commandment came - forbidding all irregular desire; for the apostle sees in this the spirit of the whole law.
sin revived - “came to life”; in its malignity and strength it unexpectedly revealed itself, as if sprung from the dead.
and I died - “saw myself, in the eye of a law never kept and not to be kept, a dead man.”