Biblical Tools

Besides the Bible itself [I use the NKJV], the one tool that I use the most is the Topical Concordance in the New Open Bible that I own. I don’t use this specific Bible to preach or teach out of, because the extra material makes it unwieldy, but the topical concordance is indispensable to my writing and teaching.  What tool do you use the most?

#bible-study, #concordance, #nkjv