Was Israel's keeping of the Feast Days and Law enough without faith?
No. Israel's keeping of the Feast Days, sacrifices, and the Law to the letter was not enough because they did it without faith. They sought their own righteousness and left faith out; without faith it is impossible to please God, in the Old Testament economy or today.
Les explains that Israel was no different from many today who perform rituals by rote without faith. They kept the Feast Days, followed the sacrifices, and followed the Law to the letter, but with no faith. He emphasizes that without faith it is impossible to please God, just as true in the Old Testament economy as today. Christ was the object of faith Israel was expected to embrace; He came proving who He was and fulfilled over 360 distinct Old Testament prophecies, so they should have recognized Him. They missed Him because they were ignorant of God's righteousness, sought to establish their own righteousness, and did not submit to the righteousness of God. Christ is the end of the law for righteousness to everyone who believes.