What about “whosoever”?

This Bible pronoun means whoever or anyone at all. The much better question is, who will? The Bible teaches that no man will ever choose God on His own (Ps 14:1-3; Rom 3:9-18). If a person chooses to repent, believe on Jesus Christ, and live for Him, it is because God first regenerated that person and gave him spiritual life. So the best question is to ask whom God will do such things for, and the answer is each of His elect. The next best question is to ask how you can know if you are one of His elect, and the answer is to show the fruit of His elect (I Thess 1:2-4; II Pet 1:5-11).