For he had commanded the unclean spirit..... That had the rest of the devils under his authority, and power,to come out of the man; this he had done, either before, or just as he came up to him; See Gill on "Mr 5:8".
For oftentimes it had caught him; possessed him, and wrought so strongly in him, and with so much fury, that there was no governing him:and he was kept bound with chains and fetters; attempts were made to bind him, and keep him bound, but in vain: and he brake the bands;See Gill on "Mr 5:4".