Parent and Child: Rabbi Shlomo Kluger (Kehillat Yaakov; Shekalim 1) explains that when the Holy One, Blessed is He, created a person with a body and soul, He gave them as a gift to
We belong to ourselves, and God relates to us as independent children. However, when we rebel against God, it is considered as if we have stolen the gift of our lives from the Creator. A thief who cannot repay what he has stolen is sold into slavery to pay his debt. It is impossible for us to repay the Creator for the gift of life, and we are sold, so to speak, into slavery. When we offer the Half Shekel we are paying half the debt, the second half is forgiven by God, Who never completely lets go of the relationship of parent to child.
The Half-Shekel is a statement that we are acting in partnership with God, our Father. One must have intention that he is giving his half of the shekel together with God. One should focus on God as a loving parent when giving the Half Shekel. (Machberes Avodas Hashem)