One of the common arguments I hear against the biblical doctrine of irresistible grace (effectual calling) is an appeal to Acts 7:51 which declares
“You stiff-necked people, uncircumcised in heart and ears, you always resist the Holy Spirit. As your fathers did, so do you."
Oddly enough, the very Text here cited by some to demonstrate that grace is resistible contains they very language that makes a decisive argument against their own position. Indeed it is true that these persons cited resist the Holy Spirit, but look closely... the Text declares that their heart and ears are "uncircumcised". In the Old Testament this is the language used for regeneration (See Deut 29:4, 30:6 & Ezek 36:26) so being unregenerate, to resist every outward working of the Spirit, is simply acting in accordance with their corrupted, fallen nature.
People always resist the outward call of the gospel.. ALWAYS, until God opens their eyes, ears and heart to the gospel. That is called circumcision of heart, the new birth or regeneration. The work of the Spirit is manifold, regeneration being only one aspect ... The Bible declares that He may convict the unregenerate of certain sin and do many things short of regenerating grace. Anything short of regeneration CAN and will be resisted.
Paul also shows these two types of calling in his first letter to the Corinthians:
"but we preach Christ crucified, a stumbling block to Jews and folly to Gentiles, but to those who are called, both Jews and Greeks, Christ the power of God and the wisdom of God." 1 Cor 1:23-24
Notice in the Text that there is an indiscriminate outward call of the Gospel to both Jews and Gentiles, but it is universally rejected (stumbling block, folly) but to those Jesus and Gentiles who are called [among them], the power of God [unto salvation].