Complex sentence: While conversion "to" Islam is among its most supported tenets, conversion "from" Islam to another religion is considered to be the sin of apostasy according to the Hadith, and in some countries it is subject to the penalty of death.
Split into simpler sentences: While conversion "to" Islam is among its most supported tenets, conversion "from" Islam to another religion is considered to be the sin of apostasy. According to the Hadith and in some countries it is subject to the penalty of death.