Some say that the only thing hidden was that the Gentiles would be included. But that was not hidden. Prophesy said they would be saved through the Jews.
The people that say this do not understand that the thing hidden was that God would pay for the sins of the whole world through believing in the shed blood of Jesus on the cross. This is seen in the scriptures below. Satan would never have let Jesus shed His blood on a cross if He had known it. But as the scripture says, it was hidden in God.
1 Cor 2:7-10
7 But we speak the wisdom of God in a mystery, the hidden wisdom which God ordained before the ages for our glory,
8 which none of the rulers of this age knew; for had they known, they would not have crucified the Lord of glory.
9 But as it is written: "Eye has not seen, nor ear heard, Nor have entered into the heart of man The things which God has prepared for those who love Him."
10 But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God.
NKJV
The people that say this do not understand that the thing hidden was that God would pay for the sins of the whole world through believing in the shed blood of Jesus on the cross. This is seen in the scriptures below. Satan would never have let Jesus shed His blood on a cross if He had known it. But as the scripture says, it was hidden in God.
1 Cor 2:7-10
7 But we speak the wisdom of God in a mystery, the hidden wisdom which God ordained before the ages for our glory,
8 which none of the rulers of this age knew; for had they known, they would not have crucified the Lord of glory.
9 But as it is written: "Eye has not seen, nor ear heard, Nor have entered into the heart of man The things which God has prepared for those who love Him."
10 But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God.
NKJV