15 So I said, ‘Who are You, Lord?’ And He said, ‘I am Jesus, whom you are persecuting. 16 But rise and stand on your feet; for I have appeared to you for this purpose, to make you a minister and a witness both of the things which you have seen and of the things which I will yet reveal to you. Acts 26:15-16
I love Saul/Paul's testimony. He was a murderer of the people who believed in Jesus. He was famous for killing the very same people who served this Jesus who was now appearing to him. Amazing...but God knew that Saul/Paul did everything that he did with passion, determination and whole heartedly.
How many people do you know that don't know Jesus that are total hell raisers? You know the ones that you think are hopeless to ever become a God fearing person...man, those are people that when they do find Jesus they serve Him with just as much passion because whatever they do they do it with their whole heart.
The bible says to love the Lord your God with all of your heart, mind and strength. Pray for these people. Love on them. If God can change Saul into Paul then He can change anyone's heart. Ask God to show you who to pray for then don't give up!