Matthew 20:1-16 is one of several parables Jesus used to describe the Kingdom of Heaven. In it, I understand that the "householder" is God, and throughout time (here expressed as a day), He hires laborers to work in His field (the world - Mt. 13:38). Jesus describes two kinds of people: those with whom He made a covenant, a legally binding agreement (v. 2), and those who simply trust Him to be fair and just (v. 3-7). Israel was known to be God's covenant people (Gen. 17:7; Ex. 2:24); I interpret those in verse two to be Israel. The other laborers did not require a covenant agreement, but simply responded to God's call. These had faith in His Word!
At the end of the day (representing time), God will reward those who trust Him to be fair (the Church), with the same "pay" as those who required a guarantee of payment (Israel); both will spend eternity with Him. Some folks I know do not believe Israel will be there unless they trust in Jesus, and I agree. And we read in the Book of Romans that once Israel realizes who Jesus really is, they will ALL trust Him, and ALL will be saved (Rom. 11:25-29)!
It seems to me that verse sixteen has an interesting hint to the mystery we call the Rapture (1 Thes. 4:13-17). Israel was chosen first, and for two thousand years, they believed only they were God's people. Following their rejection of Jesus, the Church came into existence (Acts 2:1-4), and for two thousand years, the Church has believed only it will go to heaven. Funny how things work out, for they are actually right! The "called" will actually go first in the Rapture, but the "chosen" will see heaven coming to them (Rev. 21:1)!
The Last shall be First, but both will be there, praise God!