Both messages were "Go", or calls to action, messages resulting in the conversion of a key national figure, the Ethiopian eunuch.
The angel's responsibility as God's messenger: To tell Philip to go, and where; to help to bring the preacher and the seeker together. The angel is not sent to preach. Philip's responsibility as a redeemed sinner was to witness for Christ. Likewise it is God's will to use you
and your witness in the matter of soul-winning.
The specific guidance at that time, for Philip, was to be more than the inner voice of the Spirit, because sanctified common sense could have come down in favour of not leaving Samaria. It would not seem reason to leave a revival and go to a desert place. This guidance
of Philip by an angel, should build up our confidence in God's leading when He wants us to do a job of work. He will not leave us in doubt, even if it takes dispatching an angel to inform us. An unusual directive will be received in an unusual way.
The angel could call attention to the work at hand, and give geographic direction, but Philip had to exercise faith and obedience.
Only when we move in faith can we expect further guidance to come.
3.1. GUIDANCE BY AUDIBLE VOICE CAN BE BOTH EXTERNAL AND INTERNAL
WHO EXPERIENCED GUIDANCE BY THE EXTERNAL VOICE OF AN ANGEL, AND THE INTERNAL VOICE OF THE HOLY SPIRIT?
Acts 8:26,29 "Now an angel of the Lord spoke to Philip, saying, 'Arise and go toward the south along the road which goes down from Jerusalem to
Gaza.' This is desert. 29 Then the Spirit said to Philip, 'Go near and overtake this chariot.'" (NKJV)
WHAT KIND OF MESSAGES WERE GIVEN, AND WHAT WAS CALLED FOR?
3.2. GUIDANCE CAN COME TROUGH THE VOICE OF AN ANGEL
BOTH THE ANGEL AND PHILIP WERE GOD'S MESSENGERS. HOW DO THEIR RESPONSIBILITIES DIFFER?
WHY AN ANGEL, WHEN LATER PHILIP IS GUIDED BY THE INTERNAL VOICE OF THE SPIRIT?
WHAT IS EXPECTED OF PHILIP IN RESPONSE TO THIS DIRECT GUIDANCE?
Hebrews 11:6 "But without faith it is impossible to please him: ..." (KJV)