In my last post, we began to examine the actual conversion of the First Gentile Believers. In this post, we will pause for a moment to examine Kefa’s vision as he was napping before his lunch.
10 He began to feel hungry and wanted something to eat; but while they were preparing the meal, he fell into a trance 11 in which he saw heaven opened, and something that looked like a large sheet being lowered to the ground by its four corners. 12 In it were all kinds of four-footed animals, crawling creatures, and wild birds. 13 Then a voice came to him, “Get up, Jewish, slaughter and eat!” 14 But Jewish said, “No, sir! Absolutely not! I have never eaten food that was unclean or treif.” 15 The voice spoke to him a second time: “Stop treating as unclean what God has made clean.” 16 This happened three times, and then the sheet was immediately taken back up into heaven. ~ Acts 10:10 –16 (CJB)
This passage, along with Mark 7:19, deals with Kashrut’s dietary laws in Leviticus 11:1-47.
19 For it doesn’t go into his heart but into his stomach, and it passes out into the latrine.” (Thus, He declared all foods ritually clean.) ~ Mark 7:19 (CJB). Yeshua is responding to the question raised in Mark 7:15.
5 The P’rushim and the Torah-teachers asked him, “Why don’t your talmidim live in accordance with the Tradition of the Elders, but instead eat with ritually unclean hands?”
David H. Stern opines on this passage:
Thus, He declared all foods ritually clean, even if the meal participants have not washed their hands. But Yeshua did not, as many suppose, abolish the laws of Kashrut, and thus declare ham kosher! Since the beginning of the chapter, the subject has been ritual purity as taught by the Oral Torah concerning n’tilat-yadayim (ceremonial handwashing) and not Kashrut at all! There is not the slightest hint anywhere that foods in this verse can be anything other than what the Bible allows Jews to eat; in other words, kosher foods. 
Going back to Acts 10:12–14, Stern has this to say:
Leviticus 11 specifies that only those four-footed animals that chew the cud and have split hoofs are kosher (“fit”) for Jewish people to eat. No reptiles are allowed, and permitted birds are listed by name. In Kefa’s vision, all kinds of creatures appeared, including those that are non-kosher or treif. 
I would highly encourage you to read Leviticus 11:1-47 on your own as it will give you a better understanding of Kashrut’s issue. As we travel through Acts 10, we will run into this issue again as Kefa tries to figure out the meaning of his vision.
I have attached the sermon I gave many years ago on this issue.
In my next post, we continue to examine the First Gentile Believers’ actual conversion ~ Part 3.
 Jewish New Testament Commentary