There is only one way to have legitimate gain, is by means of the spiritual life, with responsibility and accountability, wherein God provides everything, in accordance with His divine plan and process.
Anyone who does not want to follow Gods plan, has already decided to pursue their own gain, in their own way, with total disregard for God and His plan.
To lay in wait, is an expression that describes deceitful or hidden means. This does not mean that someone is hiding in the shadows, but it does mean that their method, being not from God, is one of deceit.
To lurk, is a reference to any and all activity outside of the plan of God.
Without cause, means that they have no legitimate reason or basis or claim on whatever it is they want, and are attempting to take from others.
When God created this universe, and decreed His divine plan, it was all designed and created for believers in Christ, namely those who belong to God, and are of His family.
Anyone who does not belong to God, which is clearly by their own choice, do not have any legitimate claim on anything in this universe.
Anyone who ignores Gods plan and spiritual process, which likewise is clearly by their own choice, forfeit their rights to legitimate claims on Gods provision.
This includes all unbelievers of course, but also includes believers who do not pursue their spiritual life in accordance with Gods plan and process.
By rejecting God’s spiritual process, they choose to live outside of Gods will, and therefore are attempting to take that which was not intended for them, but was intended for others who do live inside of Gods will.
And the reasons that they do this is merely for greed and illegitimate or unjust gain. To take what was not intended for you, is nothing more than theft.
However, when an individual, being saved, lives their life within the sphere of Gods plan and design, then whatever they have or need or want, is provided by God. And that divine provision is legitimate and just.