Power Promised (Acts 1:8)

What does it mean to be filled with the Holy Spirit? How can we be sure that we are filled with the Holy Spirit? How practical the Holy Spirit is? Why is it important it is to have the Holy Spirit in working and dwelling in us?

“..No wonder Apostle Paul said to the Ephesian Christians, ‘Be filled with the Spirit’. Dear friend, this was not a suggestion. I suggest that you are to be filled with the Holy Spirit. No! It wasn’t a suggestion. It was a command— command! That means, and I have to face this question: that if I am not offering myself to be filled with the Holy Spirit, I am living in disobedience! But the wonderful news is..”