John Gill Commentary Luke 14:18

"And they all with one [consent] began to make excuse. The first said unto him, I have bought a field, and I must needs go out and see it; I pray thee have me excused." — Luke 14:18 (ASV)

And they all with one consent began to make excuse
Or, "they all together", as the Vulgate Latin version, (txab) , "in one", or "at once": in (Jeremiah 10:8) rendered "altogether"; and so the Ethiopic version, which adds, "with one voice": but their words and language were not the same: their excuses are differently expressed. Some render (apo miav) , "from one hour": or the selfsame hour; immediately, directly, as soon as ever they were bidden, they began to frame excuses; they at once agreed, as by common consent, to excuse themselves from coming.

The first said unto him, I have bought a piece of ground, or a
field, and I must needs go and see it :
he ought to have seen it before he bought it; and however, it was a very improper time, at evening, at supper time, as this was, to go and see a piece of ground; and at least it might have been put off till next morning; so that it was a mere excuse indeed.

I pray you have me excused :
coming to the supper: these were the principal men among the Jews, the Pharisees and rulers among the people; who were rich and covetous, worldly men; seeking their own worldly advantage more than their spiritual and eternal welfare, or the interest of God and religion.