The Greek verb embateuō (ἐμβατεύω) means to enter, to set foot in, to invade territory, and in the only NT occurrence (Colossians 2:18), it carries the technical sense of entering a sanctuary or mystery for initiation. Paul warns against those who go on "dwelling in detail" on angelic visions they have accessed through mystical initiation.
Colossians 2:18 is one of the most debated verses in Paul's letters. The "worship of angels" and one who is "taking his stand on visions" (embateuōn — entering into what he has seen) appears to describe someone claiming superior spiritual status through ecstatic mystical experiences, perhaps in the context of a proto-gnostic or mystery cult practice.
Paul's counter-argument is Christological: all spiritual fullness is found in Christ alone (Col. 2:9-10). No mystical initiation, no angel-mediated vision, no ecstatic experience adds anything to union with Christ. The person who goes through elaborate spiritual rituals "has lost connection with the Head" (Col. 2:19). Embateuō thus becomes a warning against spirituality that bypasses Christ for deeper spiritual experiences.