The difference between leavened and unleavened bread is found in the word itself - leaven. Leaven is what is placed in bread dough to make the bread rise. It is placed in the dough and spreads throughout the entire lump.
While the Jews were subject to various food laws, forbidding to eat several types of food (e.g. pork), the Christian is under no such restriction today.
The birthright was the natural privilege of the firstborn son. Receiving the birthright, the firstborn would become the head of the family, and would have charge of the family, including the family property.
Bible study is very important, but 2 Timothy 2:15 is not just a command to study the Bible. Being an approved workman involves much more.
It is very important that we think about what we sing in our worship to God if we want to be pleasing to Him.
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