The Catechism of the Catholic Church says this about Baptism. “The different effects of Baptism are signified by the perceptible elements of the sacramental rite. Immersion in water symbolizes not only death and purification, but also regeneration and renewal. Thus the two principal effects are purification from sins and new birth in the Holy Spirit.

“By Baptism all sins are forgiven, original sin and all personal sins, as well as all punishment for sin. In those who have been reborn nothing remains that would impede their entry into the Kingdom of God, neither Adam's sin, nor personal sin, nor the consequences of sin, the gravest of which is separation from God.” 1262-1263

God’s love for us is shown in his forgiveness of our sins at the moment of baptism. This is made possible through the death and resurrection of Jesus. At the moment we are baptized our slate is wiped clean through the saving power of the blood of Christ. However, the temporal consequences of the sin of Adam and Eve remain, such as “suffering, illness, death and the inclination to sin.”  These are the “thorns of flesh” which Paul speaks of. But these “weaknesses” are opportunities to grow in our relationship with God, depending on him more and more.  They can be stepping stones on our journey to God or stumbling blocks, hindering our progress. The grace of baptism is there for us for the purpose of overcoming these weaknesses. Renewing our baptismal promises stirs up these graces in those moments.