Jamieson, Fausset and Brown on Acts 15:28-29

28-29. For it seemed good to the Holy Ghost and to us, &c.--The One, inwardly guiding to and setting His seal on the decision come to: the other, the external ecclesiastical authority devoutly embracing, expressing, and conveying to the churches that decision:--a great principle this for the Church in all time.

to lay upon you no greater burden than these necessary things ... from which if ye keep yourselves, ye shall do well--The whole language of these prohibitions, and of Ac 15:20, 21, implies that they were designed as concessions to Jewish feelings on the part of the Gentile converts, and not as things which were all of unchanging obligation. The only cause for hesitation arises from "fornication" being mixed up with the other three things; which has led many to regard the whole as permanently prohibited. But the remarks on Ac 15:20 may clear this (see on Ac 15:20). The then state of heathen society in respect of all the four things seems the reason for so mixing them up.