Day of Decision

My Sir, my question is about a verse in Surah Al-Mursalat: “…So when stars are effaced. And when the heaven is cloven asunder. And when the mountains are carried away by wind. And when the apostles are collected at the appointed time, For what day is it timed? For the Day of Decision. And what knowest thou what the Day of Decision is? Woe on that day Unto the beliers…“ (The Holy Qur’an Surah Al-Mursalat 8-15).
My question is about the Day of Decision… is it a signal of the Blessed Emergence, and is it one of the signs, and is it (rejecters) a signal for rejecters of you?? I ask your permission to clarify this.