John Gill Commentary Matthew 9:31

"But they went forth, and spread abroad his fame in all that land." — Matthew 9:31 (ASV)

But they, when they were departed
That is, out of the house where they received their cure, and out of the city; for it appears, by what follows, they went into other parts, where it is probable they might originally belong; they

spread abroad his fame in all that country.
This they did, not in contempt of Christ and his orders; but rather out of gratitude to their benefactor, and through an honest zeal to spread his honour and glory: though they are not to be commended for disregarding the command of Christ; for, not our affection, but Christ's will, is to be the rule of our actions.