The Year of the Lord's Favor

Luke 4:14-19

14 Jesus returned to Galilee in the power of the Spirit, and news about him spread through the whole countryside. 15 He taught in their synagogues, and everyone praised him. 16 He went to Nazareth, where he had been brought up, and on the Sabbath day he went into the synagogue, as was his custom. And he stood up to read. 17 The scroll of the prophet Isaiah was handed to him. Unrolling it, he found the place where it is written: 18 "The Spirit of the Lord is on me, because he has anointed me to preach good news to the poor. He has sent me to proclaim freedom for the prisoners and recovery of sight for the blind, to release the oppressed, 19 to proclaim the year of the Lord's favor."

I found John Gill's Exposition in http://www.studytoolsbible.com/ is very encouraging.

To preach the acceptable year of the Lord.
The time which he willed and fixed for the redemption of his people, and in which he showed his goodwill and pleasure unto sinful men, in the gift of his Son to them, and for them; and which, as the Arabic and Syriac versions render it, was a time "acceptable to the Lord": the sufferings of Christ were according to his will; his sacrifice was of a sweet smelling savour to him; his righteousness he was well pleased with; and the satisfaction and atonement for sin he made was a plenary and complete one: all Christ did, and suffered, were grateful to God, because hereby his perfections were glorified, his purposes, counsel, and covenant were accomplished, and his people saved. The Persic version renders it, "to preach the law acceptable to God", neither agreeable to the original text, nor its sense; for Christ was sent to preach the Gospel, and not the law.