Take the practice of "tithing" (giving away a tenth of your produce to, among other things, support those whose job it was to look after God's temple in Jerusalem). Sombre, right? Nope!
This is what Moses says "You shall tithe all the yield of your seed that comes from the field year by year. And before the LORD your God, in the place that he will choose, to make his name dwell there (i.e., Jerusalem) you shall eat the tithe of your grain, of your wine, and of your oil, and of the firstborn of your herd and flock" (Deuteronomy 14). They were to use their tithe to have a great big feast in God's presence! A very sombre, religious feast? Nope! Moses continues: "if the way (to Jerusalem) is too long for you, so that you are not able to carry the tithe... then you shall turn it into money... and go to the place that the LORD your God chooses (Jerusalem) and spend the money for whatever you desire - oxen or sheep or wine or strong drink, whatever your appetite craves. And you shall eat there before the LORD your God and rejoice, you and your household." This 'law' was about celebrating - about roast beef, roast lamb, good wine, great beer, and time with family to rejoice together in God's presence! The only other 'rule' about tithing in Deuteronomy 14 is that they're to invite the poor (immigrants, widows, orphans, etc) to feast with them.
How different the Bible can be to how we imagine it! So let's read it, and (when it does seem strange to us) try to understand it. If you have questions, let me know. If you're new to the Bible, try reading "the gospel of Mark". It might just change your life!