Let’s make it personal. Why Pentecost? First of all it was a promise given to the believer and secondly it was a command authored by Jesus Himself telling the believers to wait in Jerusalem for the promise.
Why did they need it? We need all the help we can get. God assures us that what we need is available to us through His purpose in life for us, Covenant relationship, His Son Jesus and the Holy Spirit. The promises of God are for us but they do not just drop out of the sky at random.
I believe all the disciples were saved and followers of Jesus. I suppose you could question Judas, but that is another subject. Even they were followers and students of Jesus and His teachings, they were incomplete in themselves. They need more. The problems they would face, the temptations they would have to deal with and the challenges that lay before them were more than they could handle. The call upon their lives made them a bigger target.
When Peter and John were going up to the Temple to pray and they came across the lame man, it wasn’t just Peter but it was the anointing that had been given him on the day of Pentecost in that upper room that enabled him to face the situation successfully.
When Paul and Silas were bleeding, hurting, imprisoned and falsely accused and were bound in that prison, it wasn’t their good nature that brought them through. They began to sing and to pray because He that was within them was greater than he that was in the world. They were able to look beyond the natural, beyond their circumstances and see victory.
Satan is still wreaking havoc in this world. He is particularly interested in the Church and the people who attend. God is calling them to higher heights and the devil is unleashing every weapon he possesses to discourage, confuse, rob, steal, separate and kill if possible. Every believer is a target but all Satan can do is intimidate, threaten, lie, belittle and cause strife.
All power is in the hand of Jesus Christ. The devil is defeated. But just because he is defeated doesn’t mean he has quit trying. He will destroy you if you let him. If you will believe a lie, that lie might as well be true. Why? If you believe you can’t, you won’t even try. If the devil convinces you that you are unworthy, you will not press in with faith believing. If someone asked you if you are righteous you would probably say heaven’s no, not me. What about the Word of God that says your righteousness has been given by God? (Isa. 54:17). It is the Holy Ghost that came on Pentecost that quickens your spirit and helps you overcome your doubts and fears through making the Word of God come alive to you. Do you have to be a Pentecostal to go to Heaven? Absolutely not. Pentecost addresses a deeper relationship. It is not a denomination. Acts 2:39 For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call. Are you part of “all”? Ask God. Read the Word. God wants you to know His will for you.