We say the Bible is inerrant. What does that mean?
The Bible says that Jesus was in the grave for three days. Does that mean he was in the grave exactly 72 hours? That cannot be the case. He died late on good Friday. The women at the tomb discovered the resurrection early Sunday morning. That is not 72 hours.
You can infer the value of pi from 1Kings 7:23 “And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it round about.” We know that pi can be calculated by the circumference (30 cubits for the molten sea) divided by the diameter (10 cubits for the molten sea). That gives us a value of pi of 3. Yet pi is 3.14…
Both of these examples illustrate what we mean by inerrant. We mean the Bible is completely accurate as it was understood within the culture and language of the day.
The gospel writers were speaking within the context of Jewish syntax and culture. The culture and language called any part of a day a day when counting days. So, Jesus was in the grave late Friday night, all day Saturday, and part of Sunday morning. That is three days using the diction of the time.
Ancient writers usually used approximations for measurements with the exception of a few ancient mathematical texts. A calculated value of 3 for pi is completely reasonable when you understand the unit of measurement. A cubit was the length from your elbow to the tip of your middle finger. That can range from 15 to 21 inches. That is a very rough approximation.
This is completely consistent with how we use language today. How old are you? I am 58 years old. Wait, I am 58 years and 6 months old. Wait I am 58 years, 6 months, and 5 days old.
Am I wrong when I say I am 58 years old? Of course not. Neither is the Bible wrong when it says Jesus was in the grave for three days or the bowl had a circumference of 30 cubits and a diameter of 10 cubits.