"Infallible Proofs"

"Infallible Proofs" (a token, a mark, a sure sign)
"To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God." (Acts 1:3)

Matthew B. Brown tells us that the Greek word translated as “infallible proofs” in Acts 1:3 is a derivative of tekmerion which means “a sure sign,” “a mark,” “a token”. (All Things Restored, p. xiii, footnote #11. He uses Vine’s Complete Expository Dictionary of Old and New Testament Words and The New Strong’s Exhaustive Concordance of the Bible.)

“I will clothe him with thy robe, and strengthen him with thy girdle. . . . And the key of the House of David will I lay upon His shoulders, so He shall open and none shall shut, and none shall open. And I will fasten Him as a nail in a sure place." (Isaiah 22:21–23)