Passage
And straightway they forsooke their nets, and folowed him.
And straightway they forsooke their nets, and folowed him.
Mark 1:16 And as he walked by the sea of Galile, he saw Simon, and Andrew his brother, casting a net into the sea, (for they were fishers.)
Mark 1:17 Then Iesus said vnto them, Folow me, and I will make you to be fishers of men.
Mark 1:18 And straightway they forsooke their nets, and folowed him.
Mark 1:19 And when hee had gone a litle further thence, he sawe Iames the sonne of Zebedeus, and Iohn his brother, as they were in the ship, mending their nets.
Mark 1:20 And anon hee called them: and they left their father Zebedeus in the shippe with his hired seruants, and went their way after him.
The verse centers on "straightway", "forsooke", "nets", and "folowed". It is saying that the verse draws attention to "straightway" and "forsooke", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 17's "Then Iesus said vnto them Folow me..." into verse 19's "And when hee had gone a litle...", so "straightway" and "forsooke" belong inside that flow. In Mark context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "straightway" and "forsooke" with trust shaped by these words, not by a vague optimism outside the passage.