I'm deliberately slowing down with these two verse because we live in an age when we are a bit schizophrenic on the idea of judgement. We are big no the idea that no one has the right to judge me and yet our cultures passes judgements all the time on others; what they wear, how they parent, the state of their marriage, and so on. But it is also often a criticism that is levelled at the church - Christians are perceived as being judgemental and condemning. One of the greatest problems our society has with God is the idea of God as judge. That fear of judgement has infected us as Christians in both a positive and negative way so its worth pausing and meditating over verses like these.
The section begins with two negatives (see I told you it was negative says the voice of our society), "Judge not... condemn not..." More literally Jesus is saying "Stop judging... condemning..." But Jesus isn't saying all and every judgement is wrong, but he is saying stop the fault finding, nit-picking and criticism of others. God calls us not to be constantly critical where it doesn't matter - how often are we critical where we shouldn't be and lack judgement when we should be.
Instead the believer is to be marked by the two positives; "forgive... give". Not as one off things but as a constant repetitive generous action. This should be the normal everyday attitude of the believer, forgiving and giving. We are to be focused on and pursue the positive well being of others. Such an attitude flows from our experience of God's forgiveness and blessing. And God is pleased and blesses those who have that attitude, those who are just like their heavenly Father.
How counter cultural would we be today if in our workplaces instead of criticising we forgave and were generous with our praise? How would it change our families if we were quick to forgive rather than find fault? As God's children, redeemed, forgiven, given every blessing we are to show the contagious love and character which God has shown us to others.