Oh (O) how I love that word in its Biblical context. It stands for an abundant and abounding outpouring, starting with Gods love and grace towards mankind. If the many died by the trespass of the one man, how much more did God’s grace and the gift that came by the grace of the one man, Jesus Christ, overflow to the many! (Romans 5:15).
Overflow stands for the blessings the Lord will bring when we honor Him by giving joyfully and generously. Proverbs 3:9-10 says: Honor the Lord with your wealth, with the firstfruits of all your crops; then your barns will be filled to overflowing, and your vats will brim over with new wine.
And yes, it stands for the sheer joy that we can experience when we are in Gods will, living by His Word. Psalm 119:171, May my lips overflow with praise, for you teach me your decrees. God is a God of healthy overflow, He always gives more than enough, whatever it is we need. And because He is so good and His love is so abundant, we can spill it all around us :)
May the Lord make your love increase and overflow for each other and for everyone else, just as ours does for you. (1 Thessalonians 3:12).