God uses any time, place, person, or thing to show His truth. Any opportunity can be used by God to save someone. However you came to be saved, assuming you are, God used the things that led up to that as opportunities to show you the truth and do his will.
Be very careful, then, how you live —not as unwise but as wise, making the most of every opportunity, because the days are evil. Therefore do not be foolish, but understand what the Lord’s will is.” Ephesians 5:15-17
Opportunities can sometimes be missed, there may be many, or you may need to ask God to help you see the opportunities.