Jesus is warning his disciples not to be deceived by anyone about what will happen. Here "lead astray" is an idiom for "deceive". AT: "deceives you concerning what will happen" (See: [[rc://en/ta/man/translate/figs-explicit]] and [[rc://en/ta/man/translate/figs-idiom]])
Possible meanings are 1) AT: "claiming my authority" or 2) "claiming that God sent them." (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-idiom]])