Strong's #302: an (pronounced an)
 a primary particle, denoting a supposition, wish, possibility or uncertainty:--(what-, where-, wither-, who-)soever. Usually unexpressed except by the subjunctive or potential mood. Also contracted for 1437.
Thayer's Greek Lexicon:
 ̓́ 
 
  an 
 
 1) has no exact English equivalent, see definitions under AV
 
  Part of Speech: particle
Relation: a primary particle
 
Usage:
This word is used 184 times:
Matthew 2:13: "be thou there until  I bring thee word: for Herod"
Matthew 5:19: "the kingdom of heaven: but  whosoever shall do and"
Matthew 5:21: "Thou shalt not kill; and  whosoever shall kill shall be in danger"
Matthew 5:22: "of the judgment: and  whosoever shall say to his brother,"
Matthew 5:22: "in danger of the council: but  whosoever shall say, Thou fool,"
Matthew 5:26: "Thou shalt by no means come out thence,  till thou hast paid the uttermost"
Matthew 5:31: "It hath been said,  Whosoever shall put away his wife, let him give"
Matthew 5:32: "say unto you, That  whosoever shall put away his wife,"
Matthew 6:5: "of the streets, that  they may be seen of men. Verily I say"
Matthew 7:12: "Therefore all things  whatsoever ye would that men should do"
Matthew 10:11: "And into  whatsoever city or town ye shall enter,"
Matthew 10:11: "is worthy; and there abide  till ye go"
Matthew 10:23: "the cities of Israel,  till the Son of man"
Matthew 10:33: "But  whosoever shall deny me before men, him"
Matthew 12:20: "flax shall he not quench,  till he send forth judgment unto"
Matthew 12:32: "And  whosoever speaketh a word against the Son"
Matthew 12:32: "of man, it shall be forgiven him: but  whosoever speaketh against"
Matthew 15:5: "But ye say,  Whosoever shall say to his father or"
Matthew 16:25: "For  whosoever will save his life shall lose"
Matthew 16:25: "life shall lose it: and  whosoever will lose his"
Matthew 16:28: "shall not taste of death,  till they see the Son"
Matthew 17:9: "the vision to no man,  until the Son of man"
Matthew 18:6: "But  whoso shall offend one of these little ones which believe"
Matthew 19:9: "And I say unto you,  Whosoever shall put away his wife,"
Matthew 21:22: "And all things,  whatsoever ye shall ask in prayer, believing,"
Matthew 21:44: "shall be broken: but on  whomsoever it shall fall, it will grind him to powder."
Matthew 22:9: "the highways, and  as many as ye shall find, bid"
Matthew 23:3: "All therefore  whatsoever they bid you observe, that observe"
Matthew 23:16: "ye blind guides, which say,  Whosoever shall swear by the"
Matthew 23:16: "temple, it is nothing; but  whosoever shall swear by"
Matthew 23:18: "altar, it is nothing; but  whosoever sweareth by"
Matthew 23:30: "of our fathers, we would not  have been partakers with them in"
Matthew 23:39: "see me henceforth,  till ye shall say, Blessed"
Matthew 24:22: "should be shortened, there should no flesh  be saved: but for the elect's sake"
Matthew 24:34: "generation shall not pass,  till all these things be fulfilled."
Matthew 24:43: "the thief would come,  he would have watched, and would not have suffered"
Matthew 24:43: "he would have watched, and would not  have suffered his house"
Matthew 25:27: "and then at my coming I  should have received mine own with usury."
Matthew 26:48: "them a sign, saying,  Whomsoever I shall kiss, that same is"
Mark 3:28: "of men, and blasphemies  wherewith soever they shall blaspheme:"
Mark 3:29: "But  he that shall blaspheme against the Holy Ghost"
Mark 3:35: "For  whosoever shall do the will of God, the same"
Mark 4:25: "For  he that hath, to him shall be given: and he"
Mark 6:10: "into a house, there abide  till ye depart from that place."
Mark 6:11: "And  whosoever shall not receive you, nor hear"
Mark 6:56: "And  whithersoever he entered, into villages, or cities,"
Mark 6:56: "border of his garment: and  as many as touched him"
Mark 8:35: "For  whosoever will save his life shall lose"
Mark 8:35: "life shall lose it; but  whosoever shall lose his"
Mark 8:38: " Whosoever therefore shall be ashamed of me and of my words"