The translations of this verse found in most English Bibles cannot be supported by the Hebrew text.
If a man also lie with mankind, as he lieth with a woman, both of them have committed an abomination: they shall surely be put to death; their blood shall be upon them. (KJV)
And a man who will lie down with a male in a woman's bed, both of them have made an abomination. Dying they will be put to death; their blood is on them.
Below is a word by word translation of this verse:
ואיש אשר ישכב את זכר משכבי אשה תועבה עשו שניהם מות יומתו דמיהם בם
V’ish asher yishkav et-zachar mishk’vei ishah to’evah asu shneihem mot yumatu d’meihem bam.
(Transliterated using modern Israeli Sephardic pronunciation.)
V’ish - This is two words. First, V’, which means and. This word cannot exist by itself, and therefore is attached to the word that comes after it, that is, ish. This word means man. Hebrew has no indefinite article (a, an), so when the definite article (the) is not used, as in this case, an indefinite article is understood. Therefore, this word translates as a man. So the first two words of this verse are And a man.
asher - This word means who, which or that, depending on context. Since it is used with a man, it would mean who. And a man who.
yishkav - This is a verb. Unlike English verbs, everything we need to know about tense and person is contained in this one word. No additional pronouns or tense markers are needed. The root of the verb is the last three letters: sh-k-v, and it means lie down. The first letter of the word, y, is not part of the root, but indicates person and tense and even gender. To translate yishkav into English will require four words. The word translates as he will lie down. If a subject is already present in the sentence, as in this case, then the pronoun of the verb (he) is omitted in translation. And a man who will lie down.
et - This word means with. And a man who will lie down with.
zachar - This word means male. The verse so far reads And a man who will lie down with a male.
mishk’vei - This is a noun. The base form of the noun is mishkav, and it can be seen that the last three letters of the base, sh-k-v, are also the three letters of the verb root above, meaning lie down. This noun means bed. Hebrew nouns have more than one form. In addition to having singular and plural forms, many nouns also have absolute and construct forms. An absolute noun stands alone, with its own meaning. A construct noun is grammatically tied to the noun that follows it. In English it often translates by placing the English word ‘of’ between the two nouns. A good example is the Hebrew Beit Lechem (Bethlehem), which in English translates as House of Bread. This is because the first word, Beit, is in the construct state. Mishk’vei is in the plural construct state, meaning beds of. It would be a good idea here to explain a bit about Hebrew prepositions: Hebrew has prepositions that correspond to ours, but doesn't always use them the same way. For example, when people leave us, in English we say that we miss them. But in Hebrew, the verb to miss is used with a preposition, and we say that we miss to them. The same works in reverse, that is, sometimes English requires a preposition when Hebrew doesn't. If a preposition can be derived from context, Hebrew will sometimes leave it out. In English, we need it. Therefore, we need to insert the English word in before the words beds of in order for the sentence to make sense in English. The verse so far reads And a man who will lie down with a male in beds of.
ishah - This is the Hebrew word for woman. Since there is no definite article (the), it is understood to mean a woman. And a man who will lie down with a male in beds of a woman. Since this sounds awkard in English, we can rephrase it as “in a woman’s bed.” And a man who will lie down with a male in a woman’s bed.
(Note: The word mishk'vei only appears three times in scripture: Gen. 49:7; Lev. 18:22; Lev. 20:13. In Genesis, it is paired with the word avicha, which means "thy father," and the phrase is correctly translated in most versions as "to thy father's bed." As in Lev. 18:22, the preposition is derived from context.)
to’evah - This is a noun. It translates as abomination. Without a definite article, it translates as an abomination. Hebrew word order often varies from ours, and this is one case where this is true. In English, this word will come later in the sentence, so we will hold off on adding it to the translation until we have finished with the next two words.
asu - This is a verb. It means make or do. This form is past tense, and translates as they have made or they have done. A subject for the verb is following in the sentence, so the word they can be left out of the translation. In English, word order is usually subject-verb-object, so in order for our translation to make sense, the next word, which is the subject, will need to come before this word and the previous word.
shneihem - This word is made of two particles combined. First is shnei, which is the construct form of the number two. Because it is construct, we add the English word of to the translation: Two of. The second particle is hem, which is called a pronominal ending. Depending on context, it translates as they, them or their (all masculine). Put together, this word means two of them, or less awkwardly, both of them. And a man who will lie down with a male in a woman’s bed, both of them have made an abomination;
mot - This is a gerund form of the verb to die. It corresponds to our word dying. And a man who will lie down with a male in a woman’s bed, both of them have made an abomination; dying.
yumatu - This is a future form of the same verb. It translates as they will be put to death. The phrase dying they will be put to death expresses the certainty of the sentence, and is rendered in some English versions as they will surely die, which is an acceptable translation. And a man who will lie down with a male in a woman’s bed, both of them have made an abomination; dying they will be put to death,
d’meihem - This word is made of two particles combined. The first is d’mei, a construct form of the word for blood. Because it is construct, we could insert of after it, but we will see further on that adding of in this case will make the translation awkward. The second particle is the pronominal ending hem, as seen above in shneihem. Put together, this word means blood of them. Since this is awkward, we would translate the word as their blood. And a man who will lie down with a male in a woman’s bed, both of them have made an abomination; dying they will be put to death, their blood.
Our next point of grammar involves the present tense forms of the verb to be. In English these forms are am, art, is and are. Hebrew has such forms, but almost never uses them, except in reference to God, or when absolutely necessary for context. The reason for this may be that the forms are too close to God's name in Hebrew. While this may seem awkward to us, there are many other languages that don't use the present tense of the verb to be. Russian, for example, has become so used to ignoring the forms, that some of them are completely obsolete. The Russian equivalent of am can't even be found in a dictionary or grammar book any more. They get along fine without it, and so does Hebrew. But English can't, so we have to insert the appropriate forms when translating. And a man who will lie down with a male in a woman’s bed, both of them have made an abomination; dying they will be put to death, their blood is.
bam - This word is a contraction. Unlike English contractions, no apostrophe is needed. It is formed by taking the preposition b, which means in, and which cannot exist as a separate word, and attaching it to the final letter of the pronominal ending hem. The resulting word means in them. As mentioned earlier, Hebrew doesn’t always use prepositions the way we do, and this is one case where English would use a different preposition to express the same concept. We would use on, so we will translate the word as on them. And a man who will lie down with a male in a woman’s bed, both of them have made an abomination; dying they will be put to death, their blood is on them.
This is the correct translation of Leviticus 20:13. It can be seen that, rather than forbidding male homosexuality, it simply forbids two males to lie down in a woman’s bed, for whatever reason. Culturally, a woman's bed was her own. Other than the woman herself, only her husband was permitted in her bed, and there were even restrictions on when he was allowed in there. Any other use of her bed would have been considered defilement. Other verses in the Law will help clarify the acceptable use of the woman's bed. (Lev. 15.)