Adam Clarke on Acts 10:31

Thy prayer is heard - See the note on Act 10:4. Cornelius prayed, fasted, and gave alms. It was in this way he looked for salvation; not to purchase it: a thought of this kind does not appear to have entered into his mind; but these were the means he used to get his soul brought to the knowledge of the truth. The reader must recollect that in the case of Cornelius there was no open vision; he used the light and power which God had already given; and behold how mightily God increased his gifts! He that hath, i.e., that uses what he has, shall receive; and no man can expect any increase of light or life, who does not improve the grace already given.