Adam Clarke on John 5:18

Making himself equal with God - This the Jews understood from the preceding verse: nor did they take a wrong meaning out of our Lord's words; for he plainly stated that, whatever was the Father's work, his was the same; thus showing that He and the Father were One. They had now found out two pretenses to take away his life: one was that he had broken the Sabbath - ελυε, dissolved, as they pretended, the obligation of keeping it holy. The other was that he was guilty of blasphemy, in making himself equal to God: for both which crimes, a man, according to the law, must suffer death. See Num 15:32; Lev 24:11, Lev 24:14, Lev 24:16.