They gather themselves together— They secretly gather together to ensnare me: they observe my steps, for they wait for my life. That is, "they have their secret meetings and consultations how they may most effectually ensnare me, and work my ruin."
Related Commentaries of Psalms 56:6
Psalms 56:6
6 They gather themselves together, they hide themselves, they mark my steps, when they wait for my soul.