The importance of obedience can be illustrated several different ways. Isaiah 1:19 states,"If you are willing and obedient you will eat the good of the land." It stands to reason therefore that if we are unwilling and disobedient we will eat the bad of the land. Would you be blessed by your Father God? Then you must practice obedience to the Son's commands. Are you washed in the blood of the Lamb? Then you must obey the one command Jesus gave specifically to you, the Church.
Let's consider another approach. Jesus said, "If you love me obey my commands." He further said, "You are my friends if you do whatsoever I command you." So, if we make it our practice to obey every command of Jesus save one, can we still be His friend? If we willfully disobey the one command given specifically to us, but strive mightily to obey all those given to the jews under the old covenant, are we striving to live in the new covenant, the one established by Jesus' shed blood, or the old covenant established by the blood of animals?
The word wait Jesus used in Acts 1:4 simply means to hang around, but it is derived from an older, more ancient word which means extreme passion. It is obvious the disciples understood Jesus to say wait with extreme passion for they fasted and prayed ten days waiting for the Holy Spirit's coming. We might point out the Holy Spirit was here before He came. In John 20:21 Jesus breathed on His disciples telling them receive ye the Holy Spirit. Curiously this is the same language found in Genesis as God breathed on man and he became a living soul. So it's not like the Holy Spirit went off somewhere and those 120 had to wait for His return. He was right there in their hearts the whole time, But they had to prepare their hearts to receive a greater measure of Him. This is why it took ten days of fasting and prayer for them to receive. If it took the disciples, who had just spent three and one half years with Jesus, ten days in fasting and prayers before they received, we should not think it strange if the experience doesn't just fall on us automatically when we pray.
Now, it is true that other Biblical accounts portray that it is very easy to receive the baptism with the Spirit, but there is very clearly two Biblical accounts. From experience I have known some people who have received immediately upon praying and some who never received. I, myself, attended every full gospel meeting within thiry miles of my house for six months asking every minister, full gospel and not to pray for me that I would receive. Several ministers tried to talk me out of getting it, but I doggedly pursued obedience and would not be talked out of my determination. We confess Jesus as Lord to be saved, how can we then turn right around and deny Him that Lordship we confessed by disobeying the first commandment given after salvation? And how can some thumb their nose at the very one who died to save them from their sins, providing an eternal home of glory for them? Some do it ignorantly, but some arrogantly.