[6:21] 1 sn The figures used here are hypocatastases (implied comparisons). There may also be an allusion to Deut 6 where the people were told to bind the law on their foreheads and arms. The point here is that the disciple will never be without these instructions. See further, P. W. Skehan, Studies in Israelite Poetry and Wisdom (CBQMS), 1-8.