“So Gideon went and prepared a kid goat and an ephah of unleavened flour. The flesh he put in a basket and the broth he put in a pot. And he went to him under the Terebinth and presented it to him. And the Angel of God said to him, ‘Take the flesh and the unleavened cakes and rest them on the rock — this one. Then pour on the broth.’ And he made it so.”
Gideon, thus, gathers a form of grain and meat offering before God. This is essentially the same offering as well later be provided by Manoah when he encounters the Angel of Yahweh (Judges 13:19). While the formulae of the offering does not fit any of the prescribed sacrifices for sin or peace, the context, though demands that this is a form of offering, not just as food for the road, as some commentators would suggest. Note the language above about a sacrifice and about Gideon seeking a sign.
Further, we see the sacrifice placed on a rock (rocks were often used as make-shift altars — 1 Samuel 14:33), designated by the Angel of Yahweh. Further, the meat and items were arranged on the rock as directed by the Angel of Yahweh. So, even though the elements themselves were chosen by Gideon, the presentation of the sacrifice itself is defined by God. Such is a reminder that our worship before God is something that ought always be marked and directed by God himself in the Word. The specifics might vary somewhat from congregation to congregation (some sing psalms, others sing hymns, still others praise songs, and others yet, sing a combination of all three; some preach through books of the Bible but others preach passages of scripture around given themes; some worship for an hour others for significantly, more, etc…), but the elements remain the same as commanded by God (Reading Scripture, Preaching, Corporate Prayer, Singing, Offerings, Sacraments, etc…).