George Herbert's "The Pulley" means that man is always restless and striving for more, and that this is necessary to force mankind to seek God and be good. The first stanza talks about how God wanted to bless mankind as much as possible. The second is one of the keys of the poem, and it states that God blessed man with everything except rest.
The first part reads, "When God at first made man, / Having a glasse of blessings standing by; / Let us (said he) poure on him all we can." God pours wisdom, pleasure, honor and other blessings on man in the second stanza. The last line of the second stanza, "Rest in the bottome lay," means that the only blessing God did not give to man was rest. In the third stanza, God becomes concerned that man "would adore my gifts in stead of me." As a result, in the fourth stanza, God decides to "keep them with repining restlesnesse." He concludes, "If goodnesse leade him not, yet wearinesse / May tosse him to my breast." So, essentially, God wants to keep man restless and weary in order to force him to turn to God for peace, since man cannot find it anywhere else.