1:18 Now the birth of (2) Jesus Christ was thus: His mother, Mary, that is, having been betrothed to Joseph, before they came together, she was found to be with child of [the] Holy Spirit.
(2) Christ is the true Emmanuel, and therefore, Jesus (that is, Saviour) is conceived in the virgin by the Holy Spirit, as foretold by the prophets.
1:18 The birth of Jesus Christ. The word rendered here birth is the same in Greek that is translated genealogy in Mt 1:1.
Mary was espoused. Not married, but engaged. Betrothal was, from the times of the patriarchs, a formal ceremony, and was regarded a binding obligation. It generally lasted a whole year before marriage. After betrothal unfaithfulness was regarded adultery.
Before they came together. Before marriage.
She was found. The angel (Lu 1:26,27) predicted her conception, and when the prediction was verified she probably did not hesitate to reveal it. Her heart would be filled with joyous pride instead of shame.
Holy Ghost. Correctly, Holy Spirit. The Divine power. Christ is the only example of such a birth in all history. His birth, like his life and his resurrection, is a miracle.
1:18-25 Let us look to the circumstances under which the Son of God entered into this lower world, till we learn to despise the vain honours of this world, when compared with piety and holiness. The mystery of Christ's becoming man is to be adored, not curiously inquired into. It was so ordered that Christ should partake of our nature, yet that he should be pure from the defilement of original sin, which has been communicated to all the race of Adam. Observe, it is the thoughtful, not the unthinking, whom God will guide. God's time to come with instruction to his people, is when they are at a loss. Divine comforts most delight the soul when under the pressure of perplexed thoughts. Joseph is told that Mary should bring forth the Saviour of the world. He was to call his name Jesus, a Saviour. Jesus is the same name with Joshua. And the reason of that name is clear, for those whom Christ saves, he saves from their sins; from the guilt of sin by the merit of his death, and from the power of sin by the Spirit of his grace. In saving them from sin, he saves them from wrath and the curse, and all misery, here and hereafter. Christ came to save his people, not in their sins, but from their sins; and so to redeem them from among men, to himself, who is separate from sinners. Joseph did as the angel of the Lord had bidden him, speedily, without delay, and cheerfully, without dispute. By applying the general rules of the written word, we should in all the steps of our lives, particularly the great turns of them, take direction from God, and we shall find this safe and comfortable.