4:1

[1]. Jesus had to be tempted to fulfill the requirements of a Saviour (Heb. 2:16,17,18).
[2]. Tempting (Gen. 22:1) is also testing (Heb. 11:17) and one of the primary instruments of testing is the Devil (see Job).

4:12-16 The quotation is from (Isa. 9:1,2). Christ's public ministry is launched with a passage that deals with both advents:

(Isa. 9:6,7) - victorious government - with Christ on the throne of David; not heaven.

See (Lk. 1:30-33; Matt. 25:31; 19:28; Ps. 102:16).

Without clear understanding of the distinction between the two advents, good theology is helpless. Spiritual... "great light" must be the light of the world (Jn. 1:4-9). Application... "shadow of death" means sinful condition (Eph. 2:1,2).

4:17 Jesus Christ, as a minister of the circumcision, (Rom. 15:8) is heralding a literal, visible kingdom which is promised to Israel. The effectiveness of this message is evidenced by (Acts 1:6).

4:18-20 The strict doctrine application has no doubt to do with Jesus Christ someday pulling us up through the waters above (Ps. 148:14).

[1]. Different kinds of fish required different methods.
[2]. The bigger the fish, the more difficult they are.

In (Matt. 4:20) they forsake their nets - in (Lk. 5:11) they forsake all.

Jesus heals Peter's mother-in-law in (Lk. 4:38), but it appears in (Matt. 8:14) which all indicates that there can be a following without true discipleship.

4:21,22 Jesus first four disciples were in pairs.

4:23 Kingdom preaching includes healing which was the first sign given and it was given to Israel (Ex. 4:1-9). Israel was always interested in signs but the one Jesus told them they should observe (Matt. 12:39,40).

4:24,25 Syria was northwest of Galilee.