acharias and Elizabeth were blameless. The word "blameless" does not mean they never sinned. It means they were "godly and upright."  But being childless was viewed as punishment for sin.  As a childless couple, they may have been considered rejected by God. The rabbis listed seven groups of people who were cut off from God. The list started with a man whose wife had no child. 
Many people godly people beat themselves up and hate themselves because they feel God has not blessed them. Even some church think those who are not blessed with the right sexual orientation, with physical ability or with great riches do not have God`s favour. But spirituality does not equal sexual orientation, physical ability or prosperity. God is big, so big sexual orientation, poverty or physical ability do not limit Him.  There are gay spiritual giants. Many intensely poor people are spiritually wealthy. From this passage, we can understand that God visits those who are society does not respect. He visits those the church feels are not worthy, are not blessed and are rejected by God.
God has always done that. He chose the smallest of nations, Israel. He chooses people who seem weak to the world to confound or shame the wise.  God uses the "little people" of society to do awesome things. And the world stands amazed. The intelligent, the gifted, the ones society runs after are blown away and embarrassed, because they are not able to do "little people" under the power of God can do.
Feel like a little person? Feeling a bit left out? Neglected by God, without God or society's blessing? That does not mean you are guilty of heinous sins. Stop beating yourself up. Wait on the Lord. And serve the Lord as you wait. That is what Zacharias did. God will bless. And He will bless in ways unexpected and impressive ways.
All of the direct descendants of Aaron were automatically priests.  There were way too many priests for routine duties.  That would be like all of the Smiths in the phone book being pastors. There would be far too many pastors. You'd have pastors falling all over pastors.
Generally, priests did not get a chance to keep the incense burning in the Most Holies, because priestly duties were assigned by drawing lots,  by Lotto G O D. There is some thought a priest might minister in the Temple one week about every six months.  William Barclay thinks a priest might go an entire life-time and never have the privilege of burning incense in the temple.  The Mishnah, an ancient Jewish commentary, indicates a priest could offer the Temple incense offering only once in his life.  Perhaps a modern equivalent of burning Temple incense would the chances of a local pastor's filling in for Billy Graham.
Zacharias was a priest. He was keeping the incense burning on the altar in front of the Most Holy Place in the Temple.  So this was a big day for Zacharias. He might have felt it was the most important day in his entire life!  After all, this was the day every priest dreamed of. 
Zacharias was serving the Lord, sending up an offering, when the angel appeared to him. The angel said his prayer was answered. In the process of his duties, Zacharias might have been praying. We are not sure if Zacharias was praying for a son or for the people.  Because of his age, Zacharias may well have given up hope for a son and may have stopped praying for a son.  Considering the nature of his duties in the Temple, it made sense to pray for the people, because after burning the incense, the priest blessed the people.  I tend to agree with those theologians who believe Zacharias was praying for the salvation of the people, when the angel appeared to him.  And the prayer for salvation was answered in a very unexpected manner. The angel tells Zacharias he is to have a son.
Verse 14. John will be a source of "joy and gladness . . . and many will rejoice over his birth." John causes rejoicing, because "he signals the beginning of God's redemptive work." 
John means "the Lord is gracious."  Zacharias understood the spiritual nature of John's work.  In Verse 77, Zacharias states John will "bring his people knowledge of salvation." John's name points to God's grace being revealed in Christ. 
The Lord touched John the Baptist, from conception. You too have been touched, from before conception. All who herald the coming of the King have a miraculous birth. Your spiritual birth is just as miraculous as John the Baptist's birth. God's hand is in your life, in your conception from before the beginning of the world. Through messengers, God whispers into your soul, "You are chosen!" You are chosen to proclaim Christ. Only you have the privilege not just of proclaiming the Christ is coming. You can proclaim Christ crucified, risen, returning and reigning. Salvation by grace is not just a hope. It is a done deal! Now that is what I call touched by an angel.
Through Jesus Christ you are not outcasts. You are sons and daughters of the King. And man do you have an inheritance! You will reign with Christ.
Advent is when churches celebrate an announcement God made through the birth of a child. As you celebrate you may be touched by an angel. Touched through acts of charity, love, courtesy. Through people, God will remind you of your spiritual birth, that you have been chosen, that you have a ministry, a purpose in life. In the coming holidays, God will touch others through your acts of love. Your deeds of charity will announce that the Jesus Christ is Lord.
The challenge and the power God gives us today is to walk out of here, into the mission field, as angels, messengers of God to touch others, so all people, regardless of sexual orientation, will be touched by an angel.