What did the council write for Gentiles to abstain from?
The council wrote that Gentiles should abstain from pollutions of idols, from fornication, from things strangled, and from blood. The decision did not trouble them further but placed these restrictions on those turned to God. These things still hold true today.
Les explains that James, acting as moderator, gave the decision that Gentiles turned to God should not be troubled, yet the council put "strings" on it by writing that they abstain from pollutions of idols, from fornication, from things strangled, and from blood. Les points out that these things were repeated and still hold true today. God has never given the human race permission to do any of these things; they remain anathema to Him. The reason is given later in verse 21.
But that we write unto them, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood.