St. Augustine - 'have not heard the gospel of Christ'

St. Leonard de Port-Maurice in his 'Few are Saved' sermon says that if an infidel who has not heard the Gospel lives according to his conscience, God would send him someone to teach him the faith or give him some inspiration, so that they have no excuse of not hearing the gospel:

"Now if these infidels have no excuse, will there be any for a Catholic who had so many sacraments, so many sermons, so many aids at his disposal?"

St. Augustine expresses the same idea here:

"For if, according to the word of truth, no one is delivered from the condemnation which was incurred through Adam except through the faith of Jesus Christ, and yet from this condemnation they shall not deliver themselves who shall be able to say they have not heard the gospel of Christ, on the ground that 'faith cometh by hearing,' how much less shall they deliver themselves who shall say 'We have not received perseverance!' For the excuse of those who say 'We have not received hearing' seems more equitable than that of those who say 'We have not received perseverance;' since it may be said, O man, in that which thou hadst heard and kept, in that thou mightest persevere if thou wouldest; but in no wise can it be said, That which thou hadst not heard thou mightest believe if thou wouldest."

St. Augustine, On Rebuke and Grace, Chapter 11 (Google Book)