Yes, we all must prepare to meet God, but Israel had to prepare itself to meet God for a matter of judgment against the nation. Amos told the people to prepare for such a meeting,

“Therefore thus will I do to you, O Israel;
Because I will do this to you,
Prepare to meet your God, O Israel!”
(Amos 4.12)

We do not want to hear that announcement, but if we do not follow the Lord Jesus Christ, we will hear something similar. Let us, therefore, give our all to be what God wants us to be, and to do so by His grace.