William Burkitt on Luke 1:13

Observe here, 1. How apprehensive this good angel was of Zacharias's surprising fear, and encourages him against it. The holy angels, though they do not express it in words, yet they pity our frailties, and suggest comfort to us. The evil angels if they might, would kill us with terror; the good angels labour altogether for our tranquility and cheerfulness. The angel said unto him, Fear not.

Observe, 2. The comfortable words spoken unto Zacharias; Thy prayer is heard, and thy wife Elizabeth shall bear thee a son. No doubt Zacharias and Elizabeth had often prayed for a child, and now God sends them one when they least expected it.

Learn hence, that sometimes God gives in a mercy to us, when we least expect it; yea, when we have given over looking for it. No doubt it was the case here, Zachary and Elizabeth being both well stricken in age.

Observe, 3. The name which the angel directed Zacharias to give his son: Thou shalt call his name John, which signifies gracious; because he was to open the kingdom of grace, and to preach the grace of the gospel through Jesus Christ. The giving of significant names to children, has been an ancient and pious practice; names which either carried a remembrance of duty or of mercy in them.