Seventy times - Vine's Expository Dictionary of New Testament Words
Seventy times[ 1,,G1441, hebdomekontakis ]
occurs in Matthew 18:22, where it is followed by hepta, seven," "seventy times seven;" RV marg. has "seventy times and seven," which many have regarded as the meaning; cp. Genesis 4:24 (Winer, in Winer-Moulton, Gram., p. 314, remarks that while this would be the strict meaning, it "would not suit the passage;" his translator, W. F. Moulton, in a footnote, expresses the opinion that it would. So also J.H. Moulton, Prol., p. 98, says: "A definite allusion to the Genesis story is highly probable: Jesus pointedly sets against the natural man's craving for seventy-sevenfold revenge the spiritual man's ambition to exercise the privilege of seventy-sevenfold forgiveness").
The Lord's reply "until seventy times seven" was indicative of completeness, the absence of any limit, and was designed to turn away Peter's mind from a merely numerical standard. God's forgiveness is limitless; so should man's be.