“So his master said, ‘Go out into the country lanes and behind the hedges and urge anyone you find to come, so that the house will be full. For none of those I first invited will get even the smallest taste of my banquet.’” Luke 14: 23-24
This is a brief part - the climax of a bigger story that Jesus told to illustrate God's attitude toward us when He offers/calls us to an opportunity to follow Him, to be part of His family and His plans and agenda. A King invites people to a banquet and those invited can't get around to showing up because they all have really practical things they need to tend to. Sorry, can't make it. Their replies make sense to them - entirely understandable and reasonable. Jesus bluntly says they are making excuses and it infuriates the King.
You ever eat a McDonalds' McRib sandwich? Set aside the debate if it's even real food, much less if it's nutritious or delicious. If you pull up to MickeyD's and order one, you will notice the signs all say "LIMITED TIME OFFER" or "FOR A LIMITED TIME". If you are into that sort of fast food, you better grab it fast because it will be gone (never mind McDonalds always brings it back eventually)
Here's the point: God's offer to you (Eternal Life, meaning, purpose, opportunity in this moment, etc.) is not fast food - don't treat it like something you can always get around to later. It is insulting to the King. It is infuriating to Him. We even understand something as meaningless as McMysteryMeat-in-Strange-Red-Sauce has a limited time availability and act accordingly if we really want it. You and I better recognize and respect the fact that God is so patient and kind - but His offers are for a limited time - Jesus finishes the story with the revelation that the King had enough of being blown off and passed the offer on to those who would respect it and respond.
So you: no excuses, move to accept and embrace what He's offering without delay while the offer is available!
what is "spark"?
Its a small thing - like the flash on a spark plug that hopefully ignites something bigger to propel you forward.