Blessed are the meek,
for they will inherit the earth.
Meekness is having humility and gentleness, but does not equal weakness. Meekness is a fruit of salvation: something which comes about when we have turned to Christ, and humility also has a part to play in the first act of salvation. We must be humble before we will turn to God for salvation. We need to be humble before we will submit to him as Lord and Saviour, before we will realise that we cannot help ourselves but that Jesus is the only way to be saved. Once we submit to him, we will start to live like christians also: obeying God's word and doing good doing things for God's glory. Meekness is not being cowardly, but being gentle - it still means that we stand up for what is right and for truth. Meekness also means not trusting in your own strength. Instead we need to trust in God's strength, give him the glory and submit to him. Instead of using power selfishly, meekness is about using it to benefit others and glorify God. It is trusting God in everything that happens and being content, instead of being anxious about life and troubled about things going 'wrong' in the world.
There is such a thing as fake meekness: claiming to be humble when you actually aren't. I once heard a quote: the moment you think that you are humble is the moment that you are not. Humility is realising that we deserve nothing, we deserve no blessing from God - only judgement. It is tied to mourning for sin and being poor in spirit. Likewise there is a fake meekness which is using gentleness as an excuse to be weak: to hide from confrontation and not stand up for the truth. We need to make sure that we don't use meekness as an excuse to hide.
'For they will inherit the earth' - This promise does not have its complete fulfilment here: we will not be exalted on this earth, in fact we will face persecution here. But when Christ returns to judge, he will exalt us. We are adopted as God's children, and we are co-heirs with Jesus. Of course, we are not equal to him, but we will inherit eternal life. This blessing is partially fulfilled here though: we are blessed through being christians. We are given access to God when we pray, we have hope and joy and assurance. We also are united with fellow believers as God's family.
This passage is almost a direct quote from Psalm 37:11
'But the meek will inherit the land and enjoy great peace.' The New testament is nothing new: it is the fulfilment of the Old. Jesus did not come to bring new laws or change God's law. He came to fulfil it. God does not change and we can trust him. His word is true.